Collecting information

Collecting accurate and comprehensive information both direct from the participants, or indirectly from records or other data is one of the major challenges to a successful epidemiological study. Epidemiological information comes from a variety of sources. These may be conveniently divided into those that are available from previously documented data and those that require the gathering of new information. Examples of the former include extracting information about individuals from their medical records, occupational records, and similar data sources. Design and choice of delivery of patient data capture forms by direct interview or telephone, by post, email, or other electronic means all require considerable thought and pilot testing. Attention to the specific wording of certain questions is crucial. This chapter therefore focuses on the issues surrounding the collection of information that otherwise would not be available: primary data collection.