skip to main content skip to footer

Partial Reliability Coefficients Applied to the Overachievement Problem

Saunders, David R.
Publication Year:
Report Number:
ETS Research Memorandum
Document Type:
Page Count:
Subject/Key Words:
Achievement Tests, Grade Prediction, Overachievement, Test Reliability


Partial reliability coefficients, correlation coefficients expressing the strength of relationship between two forms of measurement when a perfectly reliable third variable is held constant, constitute an ideal medium for evaluating certain recurrent problems in prediction, namely, those in which it is necessary to assess the relative advantages of seeking new predictor variables or of seeking more reliable measurement of predictor variables already identified. It is the thesis of this memorandum that this coefficient is the estimate which it would be desirable to have in most situations and, in particular, in the overachievement problem. A hypothetical numerical example is analyzed in which the predictor battery contains both aptitude and high school achievement, and college grade averages for two semesters are to be predicted. The unreliability of the high school grades and the analogous difficulty of determining the reliability of college grades are noted, but it is concluded, nevertheless, "that the present approach, if vigorously applied to actual data, will permit the making of important decisions in overachievement research."

Read More