Standard error of measurement

The standard error of measurement (SEM) is the standard deviation of errors of measrement that are associated with test scores from a particular groups of examinees. When used to calculate confidence bands atound obtained test scores, it can be helpful in expressing the unreliability of indicidual test scores in an understandable way. Score bands can also be used to interpret intrainducidual and interindicidual score differences. Interprester should be wary of over-interpretaion when using approximations for correctly calculated score bands. It is recommened that SEMs at various score levels be used in calculating score bands rather than a single SEM value.