We sought to develop a method for measuring imitation accuracy objectively in primary school children. Children imitated a model drawing shapes on the same computer-tablet interface they saw used in video clips, allowing kinematics of model and observers' actions to be directly compared. Imitation accuracy was reported as a correlation reflecting…

The unique conceptual framework and language of generalizability theory are presented. While this chapter is relevant to any area in which generalizability theory is applicable, it emphasizes evaluation research, and most examples come from that area. (Author/PN)

Demonstrating good reliability for the difference score in measurement, the results of this study indicate that the difference score is often highly reliable when the correlation between true change and true initial status is nonnegative. In general, when individual differences in true change are appreciable, the difference score shows strong…

Recent within-twin estimates of schooling returns are considerably higher than existing estimates. This paper shows that small ability differences among twins can yield more upward omitted-ability bias (and more upward bias overall) in the instrumental variables estimate correcting for measurement error than in the standard within-twin estimate.…

Previous studies of test item bias have investigated how different groups of examinees perform differently on a given set of items. These studies imply that examinees should be treated in a certain way because they are of a particular sex or race rather than as individuals in their own right, but it is unrealistic and unfair to assume such an…

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…