Home > Articles > Software Development & Management > Agile

Overview of Agile Development

This chapter explains why an Agile team doesn't have explicit phases of development, and how it delivers valuable software by encouraging direct dialog between the customer and developers. These ideas are then presented in terms of a software development life cycle that summarizes the self-governing activities of an Agile team during an Extreme Programming (XP) project. After completing the chapter, you should understand the basic nature of Agile development and therefore have a much better appreciation for the material presented in the rest of this book.
This chapter is from the book

What Is Different about an Agile Project?

The thing that most surprises people when they first encounter an Agile project is the absence of traditional phases such as design-code-test. In a traditional project, these activities are performed separately over weeks or months, but in an Agile project, they are repeated many times each hour as part of test-driven development (TDD), as we will explain in Section 5. Another thing that surprises people is the Agile approach to analysis, which is done throughout the project by developing short stories rather than attempting to capture all requirements upfront and then putting them in large documents. In the next few pages, we'll explain why Agile teams approach software development in this way and perhaps encourage you to adopt these ideas on your own team.

No Separate Development Phases

The trouble with phased development processes such as Waterfall1 is that teams typically spend many months working exclusively on each phase so that their feedback loops are too long. For example, only when the analysis is complete do they proceed to design, and only when the design is done do they move into the coding phase. Although exhaustive checks at the end of each phase attempt to validate the work, it is only during the testing phase that anyone actually knows whether the program meets its objectives. Therefore, the only real feedback about your work comes many months, even years, after it was completed. Waterfall treats software development like a production line, requiring perfection at each stage of the process. If there is any mistake or if the requirement changes during the process, the resulting software will not be correct. This may work when you're maintaining or adapting a mature software product, but not when you're developing new products in the face of changing or unknown requirements. In these sorts of circumstances, you need to increase the amount of feedback by drastically reducing the time between code creation and its validation.

The emphasis on perfecting a design before it is put into code results from people's fear that cost of change will rise steeply as the project progresses. In a traditional Waterfall project, this fear is justified because the long feedback loop between design and test means that any mistakes will result in a significant amount of rework. However, as Scott Ambler3 points out, in an Agile project, the feedback loop between design and test is very short, so mistakes can be corrected much more cheaply.

An Agile team eschews the whole idea of phases so that it can get valuable feedback continuously from the very start of the project by producing the only thing that really counts: working code. Indeed, by the end of the first week, many teams will have demonstrated running software to the customer with some feature that has business value. The price paid for this rapid delivery of working code is that the team doesn't produce thick documents or detailed models of the system. Instead, it just concentrates on writing the tests and code necessary to implement its customer's stories, as summarized on 6-by-4-inch index cards.

Specifying Requirements with Customer Stories

A customer story (also known as a user story4) defines a feature of the software that has value to the business funding your project. It takes the form of some executable acceptance tests and a written memo that aims to summarize the various discussions about the feature that are held between a developer and someone representing the interests of the business—in other words, the customer. In this way, a story provides a specification for a particular requirement in terms of what Ron Jeffries5 calls card, conversation, and confirmation:

  • Card—The most important information about what a feature must do is captured as bullet points on an index card; see Figure 3-1. The intention is to remind people about the general issues rather than to write some legally binding contract.
    Figure 3-1

    Figure 3-1 Story from OSPACS project: front and reverse sides of 6-by-4-inch index card

  • Conversation—The customer and developer must talk to each other if they are to really understand the requirement. The customer usually writes the card during this conversation.
  • Confirmation—Executable acceptance tests are written as a formal specification of the feature and define it when it has been successfully implemented. These tests contain the actual details of the requirement; see Section 7.

The customer owns the stories (what the software must do) and the developer owns the tasks necessary to implement them (how the software will work). At the beginning of the project, the customer will come up with a few initial stories, the ones that seem at the time to give the most value. More stories are generated as the project progresses. Sometimes stories will also be discarded as a consequence of changes to the business environment or due to the customer acquiring a better understanding of the requirement. This flexibility is the source of the Agile team's strength; it is able to respond to change. There is no need to identify all the requirements upfront, and the feedback given by working code allows the product to evolve in a way that is driven by fitness for purpose within the confines of a simple architecture.

In the next part of the chapter, you will see how customer stories are used in an XP project. However, they can also be used in a similar way by other types of Agile approaches, such as Scrum.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020