This study is concerned with the problem of measuring rate of learning in individualized instructional situations, and with the relationship between rate and a number of variables. Pupil aptitude, achievement, and classroom performance were measures correlated with learning rates in six different Individually Prescribed Instruction (IPI) mathematics units. The predictor variables (verbal and non-verbal I.Q., mental age, mathematics and reading achievement scores, number of skills learned in previous terms, attention score, and reaction to the learning situation and learning materials) analyzed singly, or as a composite predictor, did not correlate significantly with any or all of the criterion variables. No single predictor consistently predicted any rate measure. Multiple correlations showed that lack of rate measure comprehensiveness did not cause poor rate predictability. Multiple correlations and regression analysis showed the relative importance of various predictors as a function of specific units studied. Canonical correlations indicated some type of substantial relationship between the rate domain and the predictor variables domain. (WR)