8 We invited public sector contract managers who kept full logs of completed changes to share these with us, and collected over 60 in total. This sample was subsequently analysed and found to be representative of the population in terms of geographical location, project value and total number and value of changes made in 2006.
9 Logs of completed changes usually contained detailed data on the costing of changes, including the lifecycle and maintenance costs. We analysed the data to compare the cost of similar change made in different projects, and to calculate the average charges added for lifecycle and maintenance.