Software Reality
Extreme Programming

Site Map

XP Central
Case Against... Songs

Use Case Driven
Use Case Driven Object Modeling with UML: Theory and Practice
Get from use cases to working, maintainable source code. Examples use Spring Framework, JUnit and Enterprise Architect

Agile UML
Agile Development with ICONIX Process
A practical subset of agile development techniques, illustrated by example

Get Controversial!
Extreme Programming Refactored
Extreme Programming with a dose of satire
Available now:




The Case Against Extreme Programming

Release Plan Optimism


<< A Self-Referential Safety Net

From extremeprogramming.org:

"The release plan used to be called the commitment schedule ... A useable, testable system that makes good business sense delivered early is desired"

There are, of course, many different types of project contract.

Some project bids are won on the basis that "we'll do it more cheaply, and in less time than X, Y and Z competitors." This usually means that both the cost and deadline are set before we know exactly what needs to be delivered. The result is that post-bid negotiations take the form of an almost desperate wrangling of the project scope, where the customer wants as much as possible out of the deal, and the supplier (that's us) tries to cut down the scope as much as possible - at least to a sensible amount. What if the customer wants to fix scope as well as time and cost? Then you've got a problem.

XP attempts to counter this by using "Optional Scope Contracts". The theory is that the customer will be prepared to sign up for a project that runs for a fixed amount of time for a fixed price, without any commitment as to what is actually delivered. This premise is central to XP. Without an Optional Scope Contract, where scope is the biggest variable, XP cannot function.

However, there are potential pitfalls in contract negotiation. The customer may regard your sales team as "slippery", refusing to commit to any sort of concrete plan whilst apologetically explaining that "our software process won't allow it!"

Of course you can commit to a fixed scope contract anyway, but then that isn't really XP, and you would then be better off using a process that is tailored to fixed scope projects. Back to Extreme Programming Explained (Chapter 26):

"XP can accomodate the common forms of contract, albeit with slight modifications. Fixed price/fixed scope contracts, in particular, become fixed price/fixed date/roughly fixed scope contracts when run with the Planning Game."

 

>> XP's Audience

 


Software Reality XP Forum

<< Back to XP Central

<< Back to Lifecycle

All trademarks and copyrights on this page are owned by their respective owners.
Stories and articles are owned by the original author.
All the rest Copyright 1998-2008 Matt Stephens. ALL RIGHTS RESERVED.