Data detectives: uncovering systematic errors

This paper discusses in detail issues dealing with the technical aspects of designing and conducting surveys. It is intended for an audience of survey methodologists.

Secondary users of health information often assume that administrative data provides a relatively sound basis for making important planning and policy decisions. If errors are evenly or randomly distributed, this assumption may have little impact on these decisions. However, when information sources contain systematic errors, or when systematic errors are introduced during the creation of master files, this assumption can be damaging.

The most common systematic errors involve underreporting activities for a specific population; inaccurate re-coding of spatial information; and differences in data entry protocols, which have raised questions about the consistency of data submitted by different tracking agencies. The Central East Health Information Partnership (CEHIP) has identified a number of systematic errors in administrative databases and has documented many of these in reports distributed to partner organizations.

This paper describes how some of these errors were identified and notes the processes that give rise to the loss of data integrity. The conclusion addresses some of the impacts these problems have for health planners, program managers and policy makers.