One of the most common things touted about XP is that it allows for rapid change. The client can change the requirements on the fly for a very low cost – they can add features, changes features and drop features regularly as the product is developed without incurring a massive cost of change. When you work on in-house applications or custom built software, that provides a really big benefit, but when you develop off the shelf software that means that the final release may contain a mish-mash of new features and be generally unmarketable.

So how do you take advantage of the ability to change that XP provides while still maintaining focus in your product development? Essentially it comes down to having a client, usually the product manager, that keeps track of the long term view and makes sure that while a few little features can be added, and things are improved to be the most useful for end users, on the whole the release stays on track to deliver a cohesive set of new features that user’s will actually appreciate.

To a large extent, this means that the client, with the assistance of the rest of the business, engineering team and support team, plans out the aims for the release on a high level, and probably drilling down to some specifics before development starts. It’s important to write down those aims so that you can bring them with you to each planning game to make sure that you’re on track.

In XP terms, those goals are the yardstick by which you measure value. Each story needs to be evaluated against those goals to see how much value it brings to the release as a whole. The same approach comes out when doing in-house development since you tend to switch over sections of your processes to the new product at a time, so you are inclined to get each section fairly right instead of having a wide spread of largely useless features.

The flexibility of XP will allow you to suddenly add a key goal for a release because of competitive pressures, or to slip in that particular feature to close a big deal, but with some up front planning and an attentive product manager, you can still keep focussed on delivering a solid release.