Extreme programming in reducing the rework of requirement change

Requirement changes and the involved rework are inevitable if the requirement changes could not be foreseen. Extreme programming (XP) suggests the customer be on site with the developers. The requirement changes may be forecast by the on site customer from the business perspective and by the developers from the technology perspective. Extreme programming was adopted in the Lattice Trading System reengineering project. The user stories were weighed by a set of criteria which included the risk, cost, schedule, as well as the possibility to be changed. The stories were decomposed into features, and the features were organized into components. The components with less possibility to be changed were implemented earlier. Meanwhile, spikes were conducted when the decisions were being made for some critical tasks. In such a way, most components were completed without any change to their functional features while few components were implemented with large modification. The overall effort of rework was reduced considerably with this approach. Compared with the small cost for managing the change possibility, the method introduced in this paper is of significant worth.