3 In the first half of 2007, we carried out a census of all 171 projects within the study scope. Approximately half of these projects were schools and hospitals; the remainder was split between 9 other sectors. The combined capital value of the projects included in the census was £14 billion. The questionnaire was returned by public sector contract managers from 153 projects representing an 89 per cent response rate. The non-responses were distributed relatively evenly between sectors. The reasons given for failing to respond include a lack of available data and workload pressures.
4 The questionnaire asked for detailed factual information about changes made in 2006, with a focus on cost and processing issues. The main topic headings were:
■ Summary cost data on changes made in 2006.
■ Further details relating to major changes (with a present value of £100,000 or greater) made in 2006.
■ Breakdown of changes (by origin, type, funding method, validation technique and timescale).
■ Processing of changes.
■ Contract management.
5 In the majority of cases we also obtained a more detailed breakdown of the changes by value. Four bands were chosen, following consultation with PUK and others, to see how the management of changes differed by value: small changes (£0 to £5,000); small-medium changes (£5,000 to £30,000); medium changes (£30,000 to £100,000) and large changes (£100,000 and over). Although this approach could not completely mirror the complexity of changes made, it was considered a reasonable proxy and the nearest that could be found.
6 We later followed up the census by asking contract managers from all sectors for more detail in relation to private sector fees. We also asked for more details of any large changes (£100,000 and over); this information is set out in Appendix 2.
7 Census analysis was carried out using Excel and SPSS, excluding projects that had not provided data for a particular element of the analysis. We also carried out regression analysis to explore associations between key variables. In general, contract managers provided full responses to questions on number and value of changes. However, missing answers were more common for some processing questions, for instance in respect of timescales taken to process changes. This reflected the varying levels of detail in the public sector's records of changes.