In assessment programs where scores are reported for individual examinees, it is desirable to have responses to performance exercises graded by more than one rater. If more than one item on each test form is so graded, it is also desirable that different raters grade the responses of any one examinee. This gives rise to sampling designs in which…

Simulations demonstrate the effects of correlated errors on the person-by-occasion design in which the confounding effect of equal time intervals results in correlated error terms in the linear model. Two specific error correlation structures were examined. Conditions under which underestimation and overestimation occur are discussed. (SLD)

The implications of serially correlated effects on the results of generalizability analyses are discussed. Simulated data are provided that demonstrate the biases that serially correlated effects introduce into the results. Serial correlation in measurement effects can have a marked influence on the impression of the dependability of measurement…