Published Online: 30 JAN 2010
Copyright © 2010 John Wiley & Sons, Inc. All rights reserved.
Corsini Encyclopedia of Psychology
How to Cite
Little, R. J. 2010. Missing Data. Corsini Encyclopedia of Psychology. 1–2.
- Published Online: 30 JAN 2010
Missing values are a common problem in psychology research. For example, in longitudinal studies, missing data arise because of attrition, that is, subjects dropping out prior to the end of the study. In surveys, some individuals provide no information because of noncontact or refusal to respond (unit nonresponse), or they fail to answer some of the questions because the topics are sensitive or because the information is hard to retrieve (item nonresponse). Information about a variable may be partially recorded, as when information is censored or classified or when time of an event (e.g., death) is not known because an individual is still alive at the termination of the study. Often psychology research involves indexes formed by summing values of particular items; missing data arise if any of the items that form the index is missing. Missing data can also arise by design, for example, when expensive or hard to collect information is recorded for only a subset of study participants.
- incomplete data;
- multiple imputation;
- weighting adjustments