This chapter describes the challenges of collecting accurate effort and cost data for large projects. To obtain data at a reasonable cost, you must carefully plan to collect only the data you need and to automate its collection. Typically, your organization’s management information system (MIS) collects cost and effort data, and may collect additional data as well. (Another term is cost collection system.) However, limitations of these systems affect the timeliness and accuracy of the data. This chapter explains the problems and identifies some solutions. Sections 22.4, 22.5, and 22.6 deal with special topics of interest to only a few organizations. Most readers will want to skip them.