Pretest-posttest experimental designs are often used in randomized control trials (RCTs) in the education field to improve the precision of the estimated treatment effects. For logistic reasons, however, pretest data are often collected after random assignment, so that including them in the analysis could bias the posttest impact estimates. Thus,…

Describes a program system which was developed for the purpose of making estimates about the nature of the distribution of test scores which will result from an administration of a test composed of items of which estimates of item-difficulty and discrimination are available. (Author/RC)

Recent research results strongly suggest that the theoretical problems of change measures have limited practical significance for measuring individual growth, and it is important to determine whether this is also the case for measuring school impact. Accordingly, in this study artifical data were used to assess the correlation between several…

The four main approaches to measuring treatment effects in schools; raw gain, residual gain, covariance, and true scores; were compared. A simulation study showed true score analysis produced a large number of Type-I errors. When corrected for this error, this method showed the least power of the four. This outcome was clearly the result of the…