RECORD LINKAGE IN A REGIONAL MENTAL-HEALTH PLANNING STUDY - ACCURACY OF UNIQUE IDENTIFIERS, RELIABILITY OF SOCIODEMOGRAPHICS, AND ESTIMATING IDENTIFICATION ERROR

Assembling information about individuals over time allows health manag ers and researchers to describe the progression of diseases, the care history of individuals and the sequences of care episodes that potenti ally result in improving individuals' health status. However, current mental health statistics generally focus on sets of events rather than groups of individuals making it impossible to distinguish between two different persons being admitted and the same person being admitted t wice. Accurate figures on treatment prevalence cannot be generated and multiservice users across time or across agencies will inflate the st atistics used to plan needed services. The capacity to link consistent ly defined bits of information together is critical to developing a re liable information system. This article examines the adequacy of using unique identifier codes to accomplish linkage by focusing on one exam ple of record linkage that incorporates mental health information from both community and institutional sectors in one region of Ontario, Ca nada. Findings indicate that unique ''cradle to grave'' identifiers do not guarantee accuracy if manual transcription is involved.