MISSING DATA - A CONCEPTUAL REVIEW FOR APPLIED PSYCHOLOGISTS

There has been conspicuously little research concerning missing data p roblems in the applied psychology literature. Fortunately, other field s have begun to investigate this issue. These include survey research, marketing, statistics, economics, and biometrics. A review of this li terature suggests several trends for applied psychologists. For exampl e, listwise deletion of data is often the least accurate technique to deal with missing data. Other methods for estimating missing data scor es may be more accurate and preserve more data for investigators to an alyze. Further, the literature reveals that the amount of missing data and the reasons for deletion of data impact how investigators should handle the problem. Finally, there is a great need for more investigat ion of strategies for dealing with missing data, especially when data are missing in nonrandom or systematic patterns.