PEARL VI : An epitome on Agile Modeling(AM)

PEARL VI : A epitome on Agile Modeling, (AM) which is a collection of values, principles, and practices for modeling software that can be applied on a software development project in an effective and light-weight manner

Agile Modeling (AM) is a practice-based methodology for effective modeling and documentation of software-based systems. Simply put, Agile Modeling (AM) is a collection of values, principles, and practices for modeling software that can be applied on a software development project in an effective and light-weight manner. As you see in Figure 1 AM is meant to be tailored into other, full-fledged methodologies such as XP or RUP, enabling you to develop a software process which truly meets your needs. In fact, this tailoring work has already been done for you in the form of the Disciplined Agile Delivery (DAD) process framework.

Figure 1. AM enhances other software processes.

Scope of AM

The values of AM, adopting and extending those of eXtreme Programming are communication, simplicity, feedback, courage, and humility. The keys to modeling success are to have effective communication between all project stakeholders, to strive to develop the simplest solution possible that meets all of your needs, to obtain feedback regarding your efforts often and early, to have the courage to make and stick to your decisions, and to have the humility to admit that you may not know everything, that others have value to add to your project efforts.

AM is based on a collection of principles, such as the importance of assuming simplicity when you are modeling and embracing change as you are working because requirements will change over time. You should recognize that incremental change of your system over time enables agility and that you should strive to obtain rapid feedback on your work to ensure that it accurately reflects the needs of your project stakeholders.

You should model with a purpose, if you don’t know why you are working on something or you don’t know what the audience of the model/document actually requires then you shouldn’t be working on it. Furthermore, you need multiple models in your intellectual toolkit to be effective. A critical concept is that models are not necessarily documents, a realization that enables you travel light by discarding most of your models once they have fulfilled their purpose.

Agile modelers believe that content is more important than representation, that there are many ways you can model the same concept yet still get it right. To be an effective modeler you need to recognize that open and honest communication is often the best policy to follow to ensure effective teamwork. Finally, a focus on quality work is important because nobody likes to produce sloppy work and that local adaptation of AM to meet the exact needs of your environment is important.
To model in an agile manner you will apply AM’s practices as appropriate. Fundamental practices include creating several models in parallel, applying the right artifact(s) for the situation, and iterating to another artifact to continue moving forward at a steady pace. Modeling in small increments, and not attempting to create the magical “all encompassing model” from your ivory tower, is also fundamental to your success as an agile modeler.

Because models are only abstract representations of software, abstractions that may not be accurate, you should strive to prove it with code to show that your ideas actually work in practice and not just in theory Active stakeholder participation is critical to the success of your modeling efforts because your project stakeholders know what they want and can provide you with the feedback that you require.

The principle of assume simplicity is a supported by the practices of creating simple content by focusing only on the aspects that you need to model and not attempting to creating a highly detailed model, depicting models simply via use of simple notations, and using the simplest tools to create your models. You travel light by single sourcing information, discarding temporary models and updating models only when it hurts. Communication is enabled by displaying models publicly, either on a wall or internal web site, through collective ownership of your project artifacts, through applying modeling standards, and by modeling with others. Your development efforts are greatly enhanced when you apply patterns gently. Because you often need to integrate with other systems, including legacy databases as well as web-based services, you will find that you need to formalize contract models with the owners of those systems.

With an Agile Model Driven Development (AMDD) (see Figure 2) approach you typically do just enough high-level modeling at the beginning of a project to understand the scope and potential architecture of the system, and then during development iterations you do modeling as part of your iteration planning activities and then take a just in time (JIT) model storming approach where you model for several minutes as a precursor to several hours of coding.

Figure 2. Agile Model Driven Development (AMDD).

Another way to look at Agile Modeling is as a collection of best practices, as you see in Figure 3.

Figure 3. The best practices of Agile Modeling.

Core Principles:

  • Model With A Purpose. Many developers worry about whether their artifacts — such as models, source code, or documents — are detailed enough or if they are too detailed, or similarly if they are sufficiently accurate. What they’re not doing is stepping back and asking why they’re creating the artifact in the first place and who they are creating it for. With respect to modeling, perhaps you need to understand an aspect of your software better, perhaps you need to communicate your approach to senior management to justify your project, or perhaps you need to create documentation that describes your system to the people who will be operating and/or maintaining/evolving it over time. If you cannot identify why and for whom you are creating a model then why are you bothering to work on it all? Your first step is to identify a valid purpose for creating a model and the audience for that model, then based on that purpose and audience develop it to the point where it is both sufficiently accurate and sufficiently detailed. Once a model has fulfilled its goals you’re finished with it for now and should move on to something else, such as writing some code to show that the model works. This principle also applies to a change to an existing model: if you are making a change, perhaps applying a known pattern, then you should have a valid reason to make that change (perhaps to support a new requirement or to refactor your work to something cleaner). An important implication of this principle is that you need to know your audience, even when that audience is yourself. For example, if you are creating a model for maintenance developers, what do they really need? Do they need a 500 page comprehensive document or would a 10 page overview of how everything works be sufficient? Don’t know? Go talk to them and find out.
  • Maximize Stakeholder ROI. Your project stakeholders are investing resources — time, money, facilities, and so on — to have software developed that meets their needs. Stakeholders deserve to invest their resources the best way possible and not to have resources frittered away by your team. Furthermore, they deserve to have the final say in how those resources are invested or not invested. If it was your resources, would you want it any other way? Note: In AM v1 this was originally called “Maximize Stakeholder Investment”. Over time we realized that this term wasn’t right because it sounded like we were saying you needed to maximize the amount of money spent, which wasn’t the message.
  • Travel Light. Every artifact that you create, and then decide to keep, will need to be maintained over time. If you decide to keep seven models, then whenever a change occurs (a new/updated requirement, a new approach is taken by your team, a new technology is adopted, …) you will need to consider the impact of that change on all seven models and then act accordingly. If you decide to keep only three models then you clearly have less work to perform to support the same change, making you more agile because you are traveling lighter. Similarly, the more complex/detailed your models are, the more likely it is that any given change will be harder to accomplish (the individual model is “heavier” and is therefore more of a burden to maintain). Every time you decide to keep a model you trade-off agility for the convenience of having that information available to your team in an abstract manner (hence potentially enhancing communication within your team as well as with project stakeholders). Never underestimate the seriousness of this trade-off. Someone trekking across the desert will benefit from a map, a hat, good boots, and a canteen of water they likely won’t make it if they burden themselves with hundreds of gallons of water, a pack full of every piece of survival gear imaginable, and a collection of books about the desert. Similarly, a development team that decides to develop and maintain a detailed requirements document, a detailed collection of analysis models, a detailed collection of architectural models, and a detailed collection of design models will quickly discover they are spending the majority of their time updating documents instead of writing source code.
  • Multiple Models. You potentially need to use multiple models to develop software because each model describes a single aspect of your software. “What models are potentially required to build modern-day business applications?” Considering the complexity of modern day software, you need to have a wide range of techniques in your intellectual modeling toolkit to be effective (see Modeling Artifacts for AM for a start at a list and Agile Models Distilled for detailed descriptions). An important point is that you don’t need to develop all of these models for any given system, but that depending on the exact nature of the software you are developing you will require at least a subset of the models. Different systems, different subsets. Just like every fixit job at home doesn’t require you to use every tool available to you in your toolbox, over time the variety of jobs you perform will require you to use each tool at some point. Just like you use some tools more than others, you will use some types of models more than others.
  • Rapid Feedback. The time between an action and the feedback on that action is critical. By working with other people on a model, particularly when you are working with a shared modeling technology (such as a whiteboard, CRC cards, or essential modeling materials such as sticky notes) you are obtaining near-instant feedback on your ideas. Working closely with your customer, to understand the requirements, to analyze those requirements, or to develop a user interface that meets their needs, provides opportunities for rapid feedback.
  • Assume Simplicity. As you develop you should assume that the simplest solution is the best solution. Don’t overbuild your software, or in the case of AM don’t depict additional features in your models that you don’t need today. Have the courage that you don’t need to over-model your system today, that you can model based on your existing requirements today and refactor your system in the future when your requirements evolve. Keep your models as simple as possible.
  • Embrace Change. Requirements evolve over time. People’s understanding of the requirements change over time. Project stakeholders can change as your project moves forward, new people are added and existing ones can leave. Project stakeholders can change their viewpoints as well, potentially changing the goals and success criteria for your effort. The implication is that your project’s environment changes as your efforts progress, and that as a result your approach to development must reflect this reality.

You need an agile approach to change management

    .

  • Incremental Change. An important concept to understand with respect to modeling is that you don’t need to get it right the first time, in fact, it is very unlikely that you could do so even if you tried. Furthermore, you do not need to capture every single detail in your models, you just need to get it good enough at the time. Instead of futilely trying to develop an all encompassing model at the start, you instead can put a stake in the ground by developing a small model, or perhaps a high-level model, and evolve it over time (or simply discard it when you no longer need it) in an incremental manner.
  • Quality Work. Nobody likes sloppy work. The people doing the work don’t like it because it’s something they can’t be proud of, the people coming along later to refactor the work (for whatever reason) don’t like it because it’s harder to understand and to update, and the end users won’t like the work because it’s likely fragile and/or doesn’t meet their expectations.
  • Working Software Is Your Primary Goal. The goal of software development is to produce high-quality working software that meets the needs of your project stakeholders in an effective manner. The primary goal is not to produce extraneous documentation, extraneous management artifacts, or even models. Any activity that does not directly contribute to this goal should be questioned and avoided if it cannot be justified in this light.
  • Enabling The Next Effort Is Your Secondary Goal. Your project can still be considered a failure even when your team delivers a working system to your users – part of fulfilling the needs of your project stakeholders is to ensure that your system robust enough so that it can be extended over time. As Alistair Cockburn likes to say, when you are playing the software development game your secondary goal is to setup to play the next game. Your next effort may be the development of the next major release of your system or it may simply be the operations and support of the current version you are building. To enable it you will not only want to develop quality software but also create just enough documentation and supporting materials so that the people playing the next game can be effective. Factors that you need to consider include whether members of your existing team will be involved with the next effort, the nature of the next effort itself, and the importance of the next effort to your organization. In short, when you are working on your system you need to keep an eye on the future.

Supplementary Principles:

  • Content Is More Important Than Representation. Any given model could have several ways to represent it. For example, a UI specification could be created using Post-It notes on a large sheet of paper (an essential or low-fidelity prototype), as a sketch on paper or a whiteboard, as a “traditional” prototype built using a prototyping tool or programming language, or as a formal document including both a visual representation as well as a textual description of the UI. An interesting implication is that a model does not need to be a document. Even a complex set of diagrams created using a CASE tool may not become part of a document, instead they are used as inputs into other artifacts, very likely source code, but never formalized as official documentation. The point is that you take advantage of the benefits of modeling without incurring the costs of creating and maintaining documentation.
  • Open And Honest Communication. People need to be free, and to perceive that they are free, to offer suggestions. This includes ideas pertaining to one or more models, perhaps someone has a new way to approach a portion of the design or has a new insight regarding a requirement; the delivery of bad news such as being behind schedule; or simply the current status of their work. Open and honest communication enables people to make better decisions because the quality of the information that they are basing them on is more accurate.

Figure 4 depicts how the AMDD activities fit into the various iterations of the agile software development lifecycle. It’s simply another way to show that an agile project begins with some initial modeling and that modeling still occurs in each construction iteration.

Figure 4. AMDD Through the Agile Development Lifecycle.

As the name implies, AMDD is the agile version of Model Driven Development (MDD). MDD is an approach to software development where extensive models are created before source code is written. A primary example of MDD is the Object Management Group (OMG)’s Model Driven Architecture (MDA) standard. With MDD a serial approach to development is often taken, MDD is quite popular with traditionalists, although as the RUP/EUP shows it is possible to take an iterative approach with MDD. The difference with AMDD is that instead of creating extensive models before writing source code you instead create agile models which are just barely good enough that drive your overall development efforts. AMDD is a critical strategy for scaling agile software development beyond the small, co-located team approach that we saw during the first stage of agile adoption.

Figure 5 depicts a high-level lifecycle for AMDD for the release of a system. First, let’s start with how to read the diagram. Each box represents a development activity. The envisioning includes two main sub-activities, initial requirements envisioning and initial architecture envisioning. These are done during Inception, iteration being another term for cycle or sprint. “Iteration 0, or Inception”, is a common term for the first iteration before you start into development iterations, which are iterations one and beyond (for that release). The other activities – iteration modeling, model storming, reviews, and implementation – potentially occur during any iteration, including Inception. The time indicated in each box represents the length of an average session: perhaps you’ll model for a few minutes then code for several hours.

Figure 5. The AMDD lifecycle: Modeling activities throughout the lifecycle of a project.

Figure 6 depicts how the AMDD activities fit into the various iterations of the agile software development lifecycle. It’s simply another way to show that an agile project begins with some initial modeling and that modeling still occurs in each construction iteration.

Figure 6. AMDD Through the Agile Development Lifecycle.

 Envisioning

The envisioning effort is typically performed during the first week of a project, the goal of which is to identify the scope of your system and a likely architecture for addressing it. To do this you will do both high-level requirements modeling and high-level architecture modeling. The goal isn’t to write detailed specifications, that proves incredibly risky in practice, but instead to explore the requirements and come to an overall strategy for your project. For short projects (perhaps several weeks in length) you may do this work in the first few hours and for long projects (perhaps on the order of twelve or more months) you may decide to invest two weeks in this effort. Agilists highly suggest not investing any more time than this as you run the danger of over modeling and of modeling something that contains too many problems (two weeks without the concrete feedback that implementation provides is a long time to go at risk).

Through initial, high-level modeling you can gain the knowledge that you need to guide the project but choose to wait to act on it.

 Initial Requirements Modeling

For the first release of a system you need to take several days to identify some high-level requirements as well as the scope of the release (what you think the system should do). The goal is to get a good gut feel what the project is all about. For your initial requirements model you need some form of usage model to explore how users will work with your system, an initial domain model which identifies fundamental business entity types and the relationships between then, and an initial user interface modelwhich explores UI and usabilityissues.

your goal is to build a shared understanding, it isn’t to write detailed documentation. A critical success factor is to use inclusive modeling techniques which enable active stakeholder participation.

Initial Architecture Modeling

The goal of the initial architecture modeling effort is to try to identify an architecture that has a good chance of working. This enables you to set a (hopefully) viable technical direction for your project and to provide sufficient information to organize your team around your architecture (something that is particularly important at scale with large or distributed teams).

On the architecture side of things we often create free-form diagrams which explore the technical infrastructure, initial domain models to explore the major business entities and their relationships, and optionally change cases to explore potential architecture-level requirements which your system may need to support one day. In later iterations both your initial requirements and your initial architect models will need to evolve as you learn more, but for now the goal is to get something that is just barely good enough so that your team can get going. In subsequent releases you may decide to shorten Inception to several days, several hours, or even remove it completely as your situation dictates. The secret is to keep things simple. You don’t need to model a lot of detail, you simply need to model enough. If you’re writing use cases this may mean that point-form notes are good enough. If you’re domain modeling a whiteboard sketch or collection of CRC cards is likely good enough. For your architecture a whiteboard sketch overviewing how the system will be built end-to-end is good enough.

Many traditional developers will struggle with an agile approach to initial modeling because for years they’ve been told they need to define comprehensive models early in a project. Agile software development isn’t serial, it’s iterative and incremental (evolutionary). With an evolutionary approach detailed modeling is done just in time (JIT) during development iterations in model storming sessions.

 Iteration Modeling: Thinking Through What You’ll Do This Iteration

At the beginning of each Construction iteration the team must plan the work that they will do that iteration. An often neglected aspect of Mike Cohn’s planning poker is the required modeling activities implied by the technique. Agile teams implement requirements in priority order, see Figure 7, pulling an iteration’s worth of work off the top of the stack. To do this successfully you must be able to accurately estimate the work required for each requirement, then based on your previous iteration’s velocity (a measure of how much work you accomplished) you pick that much work off the stack. For example, if last iteration you accomplished 15 points worth of work then the assumption is that all things being equal you’ll be able to accomplish that much work this iteration. This activity is often referred to as the “planning game” or simply iteration planning.

Figure 7. Agile requirements change management process.

To estimate each requirement accurately you must understand the work required to implement it, and this is where modeling comes in. You discuss how you’re going to implement each requirement, modeling where appropriate to explore or communicate ideas. This modeling in effect is the analysis and design of the requirements being implemented that iteration.

With initial iteration modeling you explore what you need to build so that you can estimate and plan the work for the iteration effectively.

 Model Storming: Just In Time (JIT) Modeling

Agilists experience is that the vast majority of modeling sessions involve a few people, usually just two or three, who discuss an issue while sketching on paper or a whiteboard. These “model storming sessions” are typically impromptu events, one project team member will ask another to model with them, typically lasting for five to ten minutes (it’s rare to model storm for more than thirty minutes). The people get together, gather around a shared modeling tool (e.g. the whiteboard), explore the issue until they’re satisfied that they understand it, then they continue on (often coding). Model storming is just in time (JIT) modeling: you identify an issue which you need to resolve, you quickly grab a few team mates who can help you, the group explores the issue, and then everyone continues on as before. Extreme programmers (XPers) would call modeling storming sessions stand-up design sessions or customer Q&A sessions.

 Executable Specification via Test Driven Development (TDD)

During development it is quite common to model storm for several minutes and then code, following common Agile practices such as Test-First Design (TFD) and refactoring, for several hours and even several days at a time to implement what you’ve just modeled. For the sake of discussion test-driven design (TDD) is the combination of TFD and refactoring. This is where your team will spend the majority of its time. Agile teams do the majority of their detailed modeling in the form of executable specifications, often customer tests or development tests. Why does this work? Because your model storming efforts enable you to think through larger, cross-entity issues whereas with TDD you think through very focused issues typically pertinent to a single entity at a time. With refactoring you evolve your design via small steps to ensure that your work remains of high quality.

TDD promotes confirmatory testing of your application code and detailed specification of that code. Customer tests, also called agile acceptance tests, can be thought of as a form of detailed requirements and developer tests as detailed design. Having tests do “double duty” like this is a perfect example of single sourcing information, a practice which enables developers to travel light and reduce overall documentation. However, detailed specification is only part of the overall picture – high-level specification is also critical to your success, when it’s done effectively. This is why we need to go beyond TDD to consider AMDD.

You may even want to “visually program” using a sophisticated modeling tool such as Rational Software Architect (RSA). This approach requires a greater modeling skillset than is typically found in most developers, although when you do have teams made up with people of these skills you find that you can be incredibly productive with the right modeling tools.

Some, but not all, of the potential models that you may want to create on a software development project include:

  • Acceptance Test
  • Business Rule (Template)
  • Change Case (Template)
  • Class Responsibility Collaborator (CRC) model
  • Constraint
  • Contract model (Template)
  • Data Flow Diagram (DFD)
  • Domain Model
  • Essential/Abstract Use Case (Template)
  • Essential/Abstract User Interface Prototype
  • Feature
  • Free-Form Diagrams
  • Flow Chart
  • Glossary
  • Logical Data Model (LDM)
  • Mind Map
  • Network Diagram
  • Object Role Model (ORM) Diagram
  • Personas
  • Physical Data Model (PDM)
  • Robustness Diagram
  • Security Threat Model
  • System Use Case (Template)
  • Technical Requirement
  • UML Activity Diagram
  • UML Class Diagram
  • UML Communication/Collaboration Diagram
  • UML Component Diagram
  • UML Composite Structure Diagram
  • UML Deployment Diagram
  • UML Interaction Overview Diagram
  • UML Object Diagram
  • UML Package Diagram
  • UML Sequence Diagram
  • UML State Machine Diagram
  • UML Timing Diagram
  • UML Use Case Diagram
  • Usage Scenario
  • User Interface Flow Diagram (Storyboard)
  • User Interface Prototype
  • User Story
  • Value Stream Map

The best practices of AMDD are:

  1. Active Stakeholder Participation. Stakeholders should provide information in a timely manner, make decisions in a timely manner, and be as actively involved in the development process through the use of inclusive tools and techniques.
  2. Architecture Envisioning. At the beginning of an agile project you will need to do some initial, high-level architectural modeling to identify a viable technical strategy for your solution.
  3. Document Continuously. Write deliverable documentation throughout the lifecycle in parallel to the creation of the rest of the solution.
  4. Document Late. Write deliverable documentation as late as possible, avoiding speculative ideas that are likely to change in favor of stable information.
  5. Executable Specifications. Specify requirements in the form of executable “customer tests”, and your design as executable developer tests, instead of non-executable “static” documentation.
  6. Iteration Modeling. At the beginning of each iteration you will do a bit of modeling as part of your iteration planning activities.
  7. Just Barely Good Enough (JBGE) artifacts. A model or document needs to be sufficient for the situation at hand and no more.
  8. Look Ahead Modeling. Sometimes requirements that are nearing the top of your priority stack are fairly complex, motivating you to invest some effort to explore them before they’re popped off the top of the work item stack so as to reduce overall risk.
  9. Model Storming. Throughout an iteration you will model storm on a just-in-time (JIT) basis for a few minutes to explore the details behind a requirement or to think through a design issue.
  10. Multiple Models. Each type of model has it’s strengths and weaknesses. An effective developer will need a range of models in their intellectual toolkit enabling them to apply the right model in the most appropriate manner for the situation at hand.
  11. Prioritized Requirements. Agile teams implement requirements in priority order, as defined by their stakeholders, so as to provide the greatest return on investment (ROI) possible.
  12. Requirements Envisioning. At the beginning of an agile project you will need to invest some time to identify the scope of the project and to create the initial prioritized stack of requirements.
  13. Single Source Information. Strive to capture information in one place and one place only.
  14. Test-Driven Design (TDD). Write a single test, either at the requirements or design level, and then just enough code to fulfill that test. TDD is a JIT approach to detailed requirements specification and a confirmatory approach to testing.

 

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Welcome to Agile Pearls of Wisdom Blog

This Blog elucidates the pearls of wisdom in Agile Software Development methodology based on best practices, approaches, implementations, frameworks, checklists, cheat sheets, concepts, principles, guidelines, tools, methods, values, practices, philosophies, culture etc.

Agile software development 

Agile software development is a group of software development methods based on iterative and incremental development, where requirements and solutions evolve through collaboration between self-organizing, cross-functional teams. It promotes adaptive planning, evolutionary development and delivery, a time-boxed iterative approach, and encourages rapid and flexible response to change. It is a conceptual framework that promotes foreseen tight iterations throughout the development cycle.

Agile Development

Agile Development

The Agile Manifesto introduced the term in 2001. Since then, the Agile Movement, with all its values, principles, methods, practices, tools, champions and practitioners, philosophies and cultures, has significantly changed the landscape of the modern software engineering and commercial software development in the Internet era

Predecessors
Martin Fowler is widely recognized as one of the key founders of the agile methods.
Incremental software development methods have been traced back to 1957.In 1974, a paper by E. A. Edmonds introduced an adaptive software development process. Concurrently and independently the same methods were developed and deployed by the New York Telephone Company’s Systems Development Center under the direction of Dan Gielan. In the early 1970s, Tom Gilb started publishing the concepts of Evolutionary Project Management (EVO), which has evolved into Competitive Engineering. During the mid to late 1970s Gielan lectured extensively throughout the U.S. on this methodology, its practices, and its benefits.

So-called lightweight agile software development methods evolved in the mid-1990s as a reaction against the heavyweight waterfall-oriented methods, which were characterized by their critics as being heavily regulated, regimented, micromanaged and overly incremental approaches to development.

Proponents of lightweight agile methods contend that they are returning to development practices that were present early in the history of software development.

Agile Methodologies

Agile Methodologies

Early implementations of agile methods include Rational Unified Process (1994), Scrum (1995), Crystal Clear, Extreme Programming (1996), Adaptive Software Development, Feature Driven Development (1997), and Dynamic Systems Development Method (DSDM) (1995). These are now collectively referred to as agile methodologies, after the Agile Manifesto was published in 2001.

On February 11-13, 2001, at The Lodge at Snowbird ski resort in the Wasatch mountains of Utah, seventeen people met to talk, ski, relax, and try to find common ground and of course, to eat. What emerged was the Agile Software Development Manifesto. Representatives from Extreme Programming, SCRUM, DSDM, Adaptive Software Development, Crystal, Feature-Driven Development, Pragmatic Programming, and others sympathetic to the need for an alternative to documentation driven, heavyweight software development processes convened.

Now, a bigger gathering of organizational anarchists would be hard to find, so what emerged from this meeting was symbolic, a Manifesto for Agile Software Development signed by all participants. The only concern with the term agile came from Martin Fowler (a Brit for those who dont know him) who allowed that most Americans didnt know how to pronounce the word agile.

Alistair Cockburns initial concerns reflected the early thoughts of many participants. “I personally didn’t expect that this particular group of agilites to ever agree on anything substantive.”
But his post-meeting feelings were also shared, “Speaking for myself, I am delighted by the final phrasing [of the Manifesto]. I was surprised that the others appeared equally delighted by the final phrasing. So we did agree on something substantive.”

Naming themselves “The Agile Alliance,” this group of independent thinkers about software development, and sometimes competitors to each other, agreed on the Manifesto for Agile Software Development .

But while the Manifesto provides some specific ideas, there is a deeper theme that drives many, but not all, to be sure, members of the alliance. At the close of the two-day meeting, Bob Martin joked that he was about to make a “mushy” statement. But while tinged with humor, few disagreed with Bobs sentiments that they all felt privileged to work with a group of people who held a set of compatible values, a set of values based on trust and respect for each other and promoting organizational models based on people, collaboration, and building the types of organizational communities in which they would want to work.

At the core, Jim Highsmith believes

Agile Methodologists are really about “mushy” stuff about delivering good products to customers by operating in an environment that does more than talk about “people as our most important asset” but actually “acts” as if people were the most important, and lose the word “asset”. So in the final analysis, the meteoric rise of interest in and sometimes tremendous criticism of Agile Methodologies is about the mushy stuff of values and culture.

For example, Jim thinks that ultimately, Extreme Programming has mushroomed in use and interest, not because of pair-programming or refactoring, but because, taken as a whole, the practices define a developer community freed from the baggage of Dilbertesque corporations.

Kent Beck told the story of an early job in which he estimated a programming effort of six weeks for two people. After his manager reassigned the other programmer at the beginning of the project, he completed the project in twelve weeks and felt terrible about himself! The boss of course harangued Kent about how slow he was throughout the second six weeks. Kent, somewhat despondent because he was such a “failure” as a programmer, finally realized that his original estimate of 6 weeks was extremely accurate for 2 people and that his “failure” was really the managers failure , indeed, the failure of the standard “fixed” process mindset that so frequently plagues our industry.

According to JIm Highsmith,
This type of situation goes on every day marketing, or management, or external customers, internal customers, and, yes, even developers dont want to make hard trade-off decisions, so they impose       irrational demands through the imposition of corporate power       structures. This isnt merely a software development problem, it    runs throughout Dilbertesque organizations.
In order to succeed in the new economy, to move aggressively into  the era of e-business, e-commerce, and the web, companies have to  rid themselves of their Dilbert manifestations of make-work and    arcane policies. This freedom from the inanities of corporate life attracts proponents of Agile Methodologies, and scares the         begeebers  out of traditionalists. Quite frankly, the Agile        approaches scare corporate bureaucrats at least those that are     happy pushing  process for process sake versus trying to do the    best for the "customer" and deliver something timely and tangible  and "as   promised" because they run out of places to hide.
The Agile movement is not anti-methodology, in fact, many of them  want to restore credibility to the word methodology. They want to  restore a balance. They  embrace modeling, but not in order to file some diagram in a dusty corporate repository. They embrace        documentation, but not hundreds of pages of never-maintained and   rarely-used tomes. They plan, but recognize the limits of planning in a turbulent environment. Those who would brand proponents of XP or SCRUM or any of the other Agile Methodologies as "hackers" are  ignorant of both the methodologies and the original definition of  the term hacker.

The meeting at Snowbird was incubated at an earlier get together of Extreme Programming proponents, and a few “outsiders,” organized by Kent Beck at the Rogue River Lodge in Oregon in the spring of 2000. At the Rogue River meeting attendees voiced support for a variety of “Light” methodologies, but nothing formal occurred. During 2000 a number of articles were written that referenced the category of “Light” or “Lightweight” processes. A number of these articles referred to “Light methodologies, such as Extreme Programming, Adaptive Software Development, Crystal, and SCRUM”. In conversations, no one really liked the moniker “Light”, but it seemed to stick for the time being.

In September 2000, Bob Martin from Object Mentor in Chicago, started the next meeting ball rolling with an email; “I’d like to convene a small (two day) conference in the January to February 2001 timeframe here in Chicago. The purpose of this conference is to get all the lightweight method leaders in one room. All of you are invited; and I’d be interested to know who else I should approach.” Bob set up a Wiki site and the discussions raged.

Early on, Alistair Cockburn weighed in with an epistle that identified the general disgruntlement with the word Light: “I don’t mind the methodology being called light in weight, but I’m not sure I want to be referred to as a lightweight attending a lightweight methodologists meeting. It somehow sounds like a bunch of skinny, feebleminded lightweight people trying to remember what day it is.”

The fiercest debate was over location! There was serious concern about Chicago in wintertime cold and nothing fun to do; Snowbird, Utah cold, but fun things to do, at least for those who ski on their heads like Martin Fowler tried on day one; and Anguilla in the Caribbean warm and fun, but time consuming to get to. In the end, Snowbird and skiing won out; however, a few people like Ron Jeffries want a warmer place next time.

The Agile Manifesto reads, in its entirety, as follows:

We are uncovering better ways of developing software by doing it and helping others do it. Through this work we have come to value:

  • Individuals and interactions over Processes and tools
  • Working software over Comprehensive documentation
  • Customer collaboration over Contract negotiation
  • Responding to change over Following a plan

That is, while there is value in the items on the right, we value the items on the left more.

  • Kent Beck
  • James Grenning
  • Robert C. Martin
  • Mike Beedle
  • Jim Highsmith
  • Steve Mellor
  • Arie van Bennekum
  • Andrew Hunt
  • Ken Schwaber
  • Alistair Cockburn
  • Ron Jeffries
  • Jeff Sutherland
  • Ward Cunningham
  • Jon Kern
  • Dave Thomas
  • Martin Fowler
  • Brian Marick

In 2001, the above authors drafted the agile manifesto. This declaration may be freely copied in any form, but only in its entirety through this notice.

The meaning of the manifesto items on the left within the agile software development context are:

Individuals and interactions – in agile development, self-organization and motivation are important, as are interactions like co-location and pair programming.
Working software – working software will be more useful and welcome than just presenting documents to clients in meetings.
Customer collaboration – requirements cannot be fully collected at the beginning of the software development cycle, therefore continuous customer or stakeholder involvement is very important.
Responding to change – agile development is focused on quick responses to change and continuous development.
Introducing the manifesto on behalf of the Agile Alliance, Jim Highsmith commented that the Agile movement was not opposed to methodology:

The Agile movement is not anti-methodology, in fact, many of us    want to restore credibility to the word methodology. We want to restore a balance. We embrace modeling, but not in order to file some diagram in a dusty corporate repository. We embrace documentation, but not hundreds of pages of never-maintained and rarely-used      information. We plan, but recognize the limits of planning in a    turbulent environment. Those who would brand proponents of XP or   SCRUM or any of the other Agile Methodologies as "hackers" are     ignorant of both the methodologies and the original definition of  the term hacker.
—Jim Highsmith, History: The Agile Manifesto

Agile principles
The Agile Manifesto is based on twelve principles:

  • Customer satisfaction by rapid delivery of useful software
  • Welcome changing requirements, even late in development
  • Working software is delivered frequently (weeks rather than months)
  • Working software is the principal measure of progress
  • Sustainable development, able to maintain a constant pace
  • Close, daily cooperation between business people and developers
  • Face-to-face conversation is the best form of communication (co-location)
  • Projects are built around motivated individuals, who should be trusted
  • Continuous attention to technical excellence and good design
  • Simplicity—the art of maximizing the amount of work not done—is essential
  • Self-organizing teams
  • Regular adaptation to changing circumstances

Evolution
Later, Ken Schwaber with others founded the Scrum Alliance and created the Certified Scrum Master programs and its derivatives. Ken left the Scrum Alliance in the fall of 2009, and founded Scrum.org to further improve the quality and effectiveness of Scrum.

In 2005, a group headed by Alistair Cockburn and Jim Highsmith wrote an addendum of project management principles, the Declaration of Interdependence, to guide software project management according to agile development methods.

In 2009, a movement spearheaded by Robert C Martin wrote an extension of software development principles, the Software Craftsmanship Manifesto, to guide agile software development according to professional conduct and mastery.

XP

The term XP predates the term Agile by several years. XP stands for Extreme Programming, and is a suite of practices, principles, and values invented by Kent Beck in the late ‘90s. Nowadays the principles and values are not as well known, but the practices survive. Those practices are:

The Planning Game

Development proceeds in very short iterations, typically 1-2 weeks in duration. Prior to each iteration features are broken down into very small stories. Stories are estimated by developers and then chosen by stakeholders based on their estimated cost and business value. The sum of story estimates planned for the current iteration cannot exceed the sum of estimates completed in the previous iteration.

Whole Team

The team consists of developers, business analysts, QA, project managers, etc. The team works together in a lab space or open area where collaboration and communication are maximized.

Acceptance Tests

Stories and features are defined by automated tests written by the business analysts, and QA. No story or feature can be said to be done until the suite of acceptance tests that define it are passing.

Small Releases

Systems are released to production, or pre-production very frequently. An interval of 2-3 months is the maximum. The minimum can be once per iteration.

Continuous Integration

The whole system is built and tested end-to-end several times each day. While new tests are made to pass, no previously passing tests are allowed to break. Developers must continuously keep the system in a deployable state.

Collective Ownership

Code, and other work artifacts, are not owned by individuals. Any member of the team may work on any artifact at any time.

Coding Standard

Code, and other work artifacts, look as if they were written by the team. Each team member follows the team standard for format and appearance of the artifacts.

Metaphor

Names within code and other work artifacts are chosen to be evocative of the system being created.

Sustainable Pace

Building software is a marathon, not a sprint. Team members must run at a rate they can sustain for the long haul. Overtime must be carefully controlled and limited. Tired people do not win.

Pair Programming

Code and other work artifacts are produced by pairs of individuals working together. One member of the pair is responsible for the task at hand, and the other helps out. Pairs change frequently (every two hours or so) but responsibility stays with the owner.

Pair programming, an agile development technique used by XP.

The affordability of pair programming is a key issue. If it is much more expensive, managers simply will not permit it. Skeptics assume that incorporating pair programming will double code development expenses and critical manpower needs. Along with code development costs, however, other expenses, such as quality assurance and field support costs must also be considered. IBM reported spending about $250 million repairing and reinstalling fixes to 30,000 customer-reported problems . That is over $8,000 for each defect!

In 1999, a controlled experiment run by the second author at the University of Utah investigated the economics of pair programming. Advanced undergraduates in a Software Engineering course participated in the experiment. One third of the class coded class projects as they had for years – by themselves.
The rest of the class completed their projects with a collaborative partner. After the initial adjustment period in the first program (the “jelling” assignment), together the pairs only spent about 15% more time on the program than the individuals . Development costs certainly do not double with pair programming!
Significantly, the resulting code has about 15% fewer defects . These results are statistically significant.The initial 15% increase in code development expense is recovered in the reduction in defects,

There are many specific agile development methods. Most promote development, teamwork, collaboration, and process adaptability throughout the life-cycle of the project.

Test Driven Development

Developers are not allowed to write production code until they have written a failing unit test. They may not write more of a unit test than is sufficient to fail. They may not write more production code than is sufficient to pass the failing test. The unit tests are maintained and executed as part of the build process. No previously passing unit test is allowed to fail.

Refactoring

Code, and other work artifacts, are continuously reviewed and kept as clean as possible. It is not sufficient that code works; it must also be clean.

Simple Design

The simplest design that suffices for the task at hand, is the right design. More complex and general designs may become useful later, but not now. We do not wish to carry the weight of that complexity while it is not needed. Sufficient for the day are the complexities therein.

Iterative, incremental and evolutionary

Agile methods break tasks into small increments with minimal planning and do not directly involve long-term planning. Iterations are short time frames (timeboxes) that typically last from one to four weeks. Each iteration involves a cross-functional team working in all functions: planning, requirements analysis, design, coding, unit testing, and acceptance testing. At the end of the iteration a working product is demonstrated to stakeholders. This minimizes overall risk and allows the project to adapt to changes quickly. An iteration might not add enough functionality to warrant a market release, but the goal is to have an available release (with minimal bugs) at the end of each iteration. Multiple iterations might be required to release a product or new features.

Scrum Cycle

Scrum Cycle

Efficient and face-to-face communication

No matter what development disciplines are required, each agile team will contain a customer representative, e.g. Product Owner in Scrum. This person is appointed by stakeholders to act on their behalf and makes a personal commitment to being available for developers to answer mid-iteration questions. At the end of each iteration, stakeholders and the customer representative review progress and re-evaluate priorities with a view to optimizing the return on investment (ROI) and ensuring alignment with customer needs and company goals.

Information Radiators

In agile software development, an information radiator is a (normally large) physical display located prominently in an office, where passers-by can see it. It presents an up-to-date summary of the status of a software project or other product. The name was coined by Alistair Cockburn, and described in his 2002 book Agile Software Development.A build light indicator may be used to inform a team about the current status of their project.

Very short feedback loop and adaptation cycle

A common characteristic of agile development are daily status meetings or “stand-ups”, e.g. Daily Scrum (Meeting). In a brief session, team members report to each other what they did the previous day, what they intend to do today, and what their roadblocks are.

Quality focus

Specific tools and techniques, such as continuous integration, automated unit testing, pair programming, test-driven development, design patterns, domain-driven design, code refactoring and other techniques are often used to improve quality and enhance project agility.

Philosophy
Compared to traditional software engineering, agile development is mainly targeted at complex systems and projects with dynamic, undeterministic and non-linear characteristics, where accurate estimates, stable plans and predictions are often hard to get in early stages, and big up-front designs and arrangements will probably cause a lot of waste, i.e. not economically sound. These basic arguments and precious industry experiences learned from years of successes and failures have helped shape Agile’s favor of adaptive, iterative and evolutionary development.

Adaptive vs. Predictive
Development methods exist on a continuum from adaptive to predictive. Agile methods lie on the adaptive side of this continuum. One key of adaptive development methods is a “Rolling Wave” approach to schedule planning, which identifies milestones but leaves flexibility in the path to reach them, and also allows for the milestones themselves to change. Adaptive methods focus on adapting quickly to changing realities. When the needs of a project change, an adaptive team changes as well. An adaptive team will have difficulty describing exactly what will happen in the future. The further away a date is, the more vague an adaptive method will be about what will happen on that date. An adaptive team cannot report exactly what tasks they will do next week, but only which features they plan for next month. When asked about a release six months from now, an adaptive team might be able to report only the mission statement for the release, or a statement of expected value vs. cost.

Predictive methods, in contrast, focus on analysing and planning the future in detail and cater for known risks. In the extremes, a predictive team can report exactly what features and tasks are planned for the entire length of the development process. Predictive methods rely on effective early phase analysis and if this goes very wrong, the project may have difficulty changing direction. Predictive teams will often institute a Change Control Board to ensure that only the most valuable changes are considered.

Risk analysis can be used to choose between adaptive (agile or value-driven) and predictive (plan-driven) methods

Iterative vs. Waterfall
One of the differences between agile and waterfall is that testing of the software is conducted at different stages during the software development lifecycle. In the Waterfall model, there is always a separate testing phase near the completion of an implementation phase. However, in Agile and especially Extreme programming, testing is usually done concurrently with coding, or at least, testing jobs start in early iterations.

After almost a decade of mismanagement and waste at the FBI, its CIO turned the agency’s maligned case management implementation into an agile project. Two years later, the system is live. This relative success, as well as the example of other federal agencies, shows that agile can work in Washington.

Not only that, the U.S. Government is serious about Agile. Not only is agile part of Federal CIO Steven VanRoekel’s “Future First” initiative, but the Government Accountability Office (GAO)  had issued a report on the federal government’s use of agile.

GAO identified 32 practices and approaches as effective for applying Agile software development methods to IT projects. The practices generally align with five key software development project management activities: strategic planning, organizational commitment and collaboration, preparation, execution, and evaluation. Officials who have used Agile methods on federal projects generally agreed that these practices are effective. Specifically, each practice was used and found effective by officials from at least one agency, and ten practices were used and found effective by officials from all five agencies.

Code vs. Documentation
In a letter to IEEE Computer, Steven Rakitin expressed cynicism about agile development, calling an article supporting agile software development “yet another attempt to undermine the discipline of software engineering” and translating “Working software over comprehensive documentation” as “We want to spend all our time coding. Remember, real programmers don’t write documentation.”

This is disputed by proponents of Agile software development, who state that developers should write documentation if that’s the best way to achieve the relevant goals, but that there are often better ways to achieve those goals than writing static documentation. Scott Ambler states that documentation should be “Just Barely Good Enough” (JBGE), that too much or comprehensive documentation would usually cause waste, and developers rarely trust detailed documentation because it’s usually out of sync with codes, while too little documentation may also cause problems for maintenance, communication, learning and knowledge sharing. Alistair Cockburn wrote of the Crystal method:

Crystal considers development to be a series of co-operative games, and the provision of documentation is intended to be enough to    help the next win at the next game. The work products for Crystal  include use cases, risk list, iteration plan, core domain models,  and design notes to inform on choices...however there are no       templates for these documents and descriptions are necessarily     vague, but the objective is clear, just enough documentation for   the next game. I always tend to characterize this to my team as:   what would you want to know if you joined the team tomorrow.
—Alistair Cockburn

Agile methods
Well-known agile software development methods and/or process frameworks include:

  • Adaptive Software Development (ASD)
  • Agile Modeling
  • Agile Unified Process (AUP)
  • Crystal Methods (Crystal Clear)
  • Disciplined Agile Delivery
  • Dynamic Systems Development Method (DSDM)
  • Extreme Programming (XP)
  • Feature Driven Development (FDD)
  • Lean software development
  • Scrum
  • Scrum-ban

Software development life-cycle support

The agile methods are focused on different aspects of the Software development life cycle. Some focus on the practices (e.g. XP, Pragmatic Programming, Agile Modeling), while others focus on managing the software projects (e.g. Scrum). Yet, there are approaches providing full coverage over the development life cycle (e.g. DSDM, IBM RUP), while most of them are suitable from the requirements specification phase on (FDD, for example). Thus, there is a clear difference between the various agile methods in this regard.

Agile practices
Agile development is supported by a bundle of concrete practices suggested by the agile methods, covering areas like requirements, design, modeling, coding, testing, project management, process, quality, etc. Some notable agile practices include:

  • Acceptance test-driven development (ATDD)
  • Agile Modeling
  • Backlogs (Product and Sprint)
  • Behavior-driven development (BDD)
  • Cross-functional team
  • Continuous integration (CI)
  • Domain-driven design (DDD)
  • Information radiators (Scrum board, Kanban board, Task board, Burndown chart)
  • Iterative and incremental development (IID)
  • Pair programming
  • Planning poker
  • Refactoring
  • Scrum meetings (Sprint planning, Daily scrum, Sprint review and retrospective)
  • Test-driven development (TDD)
  • Agile testing
  • Timeboxing
  • Use case
  • User story
  • Story-driven modeling
  • Velocity tracking

The Agile Alliance has provided a comprehensive online collection with a map guide to the applying agile practices.

This section explains how Primavera Systems, a vendor of project portfolio  management solutions, turned around its development organization in 2003. In  terms of value to the company, the development organization went from having low no confidence in its ability to deliver and repeated failure to meet expectations, to  being cheered for a release that was the hit of their user conference, with good  quality and twice the expected functionality. Bonuses were forthcoming for this  release. Magic? No, just leadership, hard work, and using a process that turned the  leadership and hard work into results. These are the Agile processes Primavera, a 21 year-old software company, sells project portfolio management  solutions to help firms manage all their projects, programs, and resources.  Primavera was thriving, and its growth was leading to increasingly complex client  needs; this put a strain on its ability to release a product that pleased its entire  customer base. Throughout 2002, the development organization worked overtime to  develop release 3.5. As with other projects in the past, the last three months were  particularly bad; the developers sacrificed weekends and home life to get the release  out with all of the new requirements. The result – a release seen by management as  incomplete and three weeks late, and an exhausted team with low morale.  Primavera decided to try the Agile development processes Scrum and XP to fix its  problems. Scrum is an overarching process for planning and managing development  projects, while XP prescribes individual team practices that help developers,  analysts, testers and managers perform at peak efficiency. Though they are often implemented separately, Scrum and XP are even more effective when implemented  together. Primavera adopted Scrum first to improve the way it managed product  development, then adopted XP practices to upgrade its product quality and then  customized the amalgam to suit its own needs.

The result of Primavera’s experiment is a highly satisfied customer base, and a  highly motivated, energetic development environment. Of equal value, everyone  within Primavera now has a process for working together to build the best releases  possible, and is aware of, and participates in, the tradeoff decisions involved. People  who haven’t had a chance to work together in years put their shoulders to making  each release a success, from CEO, CTO and VP’s to the entire development  organization. When the experiment started, Primavera was a very quiet, subdued  place to work. It now feels like a vibrant community.

“We pull in a lot of feedback from all of our customers and look for the similarities  across conversations with resource managers, functional managers, program  managers, and executives,” says Michael Shomberg, Primavera Vice President of  Marketing. “These methodologies are very empowering. Decisions are driven down to  where knowledge is applied. Decisions are better and communication back to the  customers is real and exciting. There are no over-promises or expectations that run  the risk of disappointment, because the customer sees on the screen what they had  in their head – or better. That’s the wow we want to experience, with our customers  and everyone in our company.”

Method tailoring
In the literature, different terms refer to the notion of method adaptation, including ‘method tailoring’, ‘method fragment adaptation’ and ‘situational method engineering’. Method tailoring is defined as:

A process or capability in which human agents determine a system development approach for a specific project situation through responsive changes in, and dynamic interplays between contexts, intentions, and method fragments.

Potentially, almost all agile methods are suitable for method tailoring. Even the DSDM method is being used for this purpose and has been successfully tailored in a CMM context. Situation-appropriateness can be considered as a distinguishing characteristic between agile methods and traditional software development methods, with the latter being relatively much more rigid and prescriptive. The practical implication is that agile methods allow project teams to adapt working practices according to the needs of individual projects. Practices are concrete activities and products that are part of a method framework. At a more extreme level, the philosophy behind the method, consisting of a number of principles, could be adapted (Aydin, 2004).

Extreme Programming (XP) makes the need for method adaptation explicit. One of the fundamental ideas of XP is that no one process fits every project, but rather that practices should be tailored to the needs of individual projects. Partial adoption of XP practices, as suggested by Beck, has been reported on several occasions.

Mehdi Mirakhorli proposes a tailoring practice that provides a sufficient road-map and guidelines for adapting all the practices. RDP (rule-description-practice) Practice is designed for customizing XP. This practice, first proposed as a long research paper in the APSO workshop at the ICSE 2008 conference, is currently the only proposed and applicable method for customizing XP. Although it is specifically a solution for XP, this practice has the capability of extending to other methodologies. At first glance, this practice seems to be in the category of static method adaptation but experiences with RDP Practice says that it can be treated like dynamic method adaptation. The distinction between static method adaptation and dynamic method adaptation is subtle.

Sabre Airline Solutions adopted XP in 2001. With its new model, Sabre does iterative development in small, simple steps. The company uses two-week iterations, and customers see a new release every one to three months. Features, called “stories,” are expressed in user terms and must be simple enough to be coded, tested and integrated in two weeks or less.
Automated unit tests (against the programmer’s criteria) and broader acceptance tests (against customer requirements) must be passed at the end of each iteration before the next can begin. Unit and acceptance tests for each feature are written before the feature is coded. If a developer has trouble writing a test, he doesn’t clearly understand the feature.
Actual coding is done in pairs by teams in open labs, promoting collective ownership of code, although individuals sometimes do the simplest tasks. Programmers are re-paired frequently, often every day or two. They sign up for the tasks they want to do and the person they want to pair with.
Every project team has an “XP coach” and an application subject-matter expert called the XP customer. The XP customer stays in or near the programming lab all or most of the time. He decides on and prioritizes product features, writes the stories for programmers and signs off on the results.
“Refactoring” code—rewriting it not to fix bugs or add features but to make it less redundant and more maintainable—is strongly encouraged. Sabre says the concept hardly existed at the company before XP because it was too difficult.

Comparison with other methods

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RAD

Agile methods have much in common with the Rapid Application Development techniques from the 1980/90s as espoused by James Martin and others. In addition to technology-focused methods, customer-and-design-centered methods, such as Visualization-Driven Rapid Prototyping developed by Brian Willison, work to engage customers and end users to facilitate agile software development.

CMMI

In 2008 the Software Engineering Institute (SEI) published the technical report “CMMI or Agile: Why Not Embrace Both” to make clear that the Capability Maturity Model Integration and Agile can co-exist. Modern CMMI-compatible development processes are also iterative. The CMMI Version 1.3 includes tips for implementing Agile and CMMI process improvement together.

Measuring agility
While agility can be seen as a means to an end, a number of approaches have been proposed to quantify agility. Agility Index Measurements (AIM) score projects against a number of agility factors to achieve a total. The similarly named Agility Measurement Index, scores developments against five dimensions of a software project (duration, risk, novelty, effort, and interaction). Other techniques are based on measurable goals. Another study using fuzzy mathematics has suggested that project velocity can be used as a metric of agility. There are agile self-assessments to determine whether a team is using agile practices (Nokia test, Karlskrona test, 42 points test).

While such approaches have been proposed to measure agility, the practical application of such metrics is still debated. There is agile software development ROI data available from the CSIAC ROI Dashboard.

Experience and adoption

Surveys
One of the early studies reporting gains in quality, productivity, and business satisfaction by using Agile methods was a survey conducted by Shine Technologies from November 2002 to January 2003. A similar survey conducted in 2006 by Scott Ambler, the Practice Leader for Agile Development with IBM Rational’s Methods Group reported similar benefits. Others claim that agile development methods are still too young to require extensive academic proof of their success.

Large-scale and distributed Agile
Large-scale agile software development remains an active research area. Agile development has been widely seen as being more suitable for certain types of environment, including small teams of experts. 157 Positive reception towards Agile methods has been observed in Embedded domain across Europe in recent years

Some things that may negatively impact the success of an agile project are:

  • Large-scale development efforts (>20 developers), though scaling strategies and evidence of some large projects have been described.
  • Distributed development efforts (non-colocated teams). Strategies have been described in Bridging the Distance and Using an Agile Software Process with Offshore Development.
  • Forcing an agile process on a development team.
  • Mission-critical systems where failure is not an option at any cost (e.g. software for avionics).
  • The early successes, challenges and limitations encountered in the adoption of agile methods in a large organization have been documented.

Agile offshore
In terms of outsourcing agile development, Michael Hackett, senior vice president of LogiGear Corporation has stated that “the offshore team … should have expertise, experience, good communication skills, inter-cultural understanding, trust and understanding between members and groups and with each other.

Comments
Agile methodologies can be inefficient in large organizations and certain types of projects. Agile methods seem best for developmental and non-sequential projects. Many organizations believe that agile methodologies are too extreme and adopt a hybrid approach that mixes elements of agile and plan-driven approaches.

The term “agile” has also been criticized as being a management fad that simply describes existing good practices under new jargon, promotes a “one size fits all” mindset towards development strategies, and wrongly emphasizes method over results.

Alistair Cockburn organized a celebration of the 10th anniversary of the Agile Manifesto in Snowbird, Utah on February 12, 2011, gathering some 30+ people who’d been involved at the original meeting and since. A list of about 20 elephants in the room (“undiscussable” agile topics/issues) were collected, including aspects: the alliances, failures and limitations of agile practices and context (possible causes: commercial interests, decontextualization, no obvious way to make progress based on failure, limited objective evidence, cognitive biases and reasoning fallacies), politics and culture.

 As Philippe Kruchten wrote in the end:
The agile movement is in some ways a bit like a teenager: very     self-conscious, checking constantly its appearance in a mirror,    accepting few criticisms, only interested in being with its peers, rejecting en bloc all wisdom from the past, just because it is fromthe past, adopting fads and new jargon, at times cocky and arrogant. But I have no doubts that it will mature further, become more    open to the outside world, more reflective, and also therefore moreeffective.

Applications Outside of Software Development
Agile methods have been extensively used for development of software products and some of them use certain characteristics of software, such as object technologies.[54] However, these techniques can be applied to the development of non-software products, such as computers, motor vehicles, medical devices, food, and clothing; see Flexible product development.

Agile development paradigms can be used in other areas of life such as raising children. Its success in child development might be founded on some basic management principles; communication, adaptation and awareness. Bruce Feiler has shown that the basic Agile Development paradigms can be applied to household management and raising children. In his TED Talk, “Agile programming — for your family”, these paradigms brought significant changes to his household environment, such as the kids doing dishes, taking out the trash, and decreasing his children’s emotional outbreaks which inadvertently increased their emotional stability. In some ways, agile development is more than a bunch of software development rules; but it can be something more simple and broad, like a problem solving guide.