Escalona points out that in psychological testing generally, there has been a shift toward a holistic view, which has brought about significant changes in the nature of the tests used, in test analysis and evaluation, and in the very aims of psychological testing procedure. The measurement of an absolute level of ability in relatively isolated functions has been replaced by an assessment of psychological functioning as a whole. The author then describes how this concept of testing has been extended to the infant. Prediction of level or kind of mental functioning implies a prediction concerning not only the characteristics of the subject, but also the constellation of the environmental variables. Thus it was found that the predictive accuracy of infant intelligence level tests could be improved when the test results proper were brought into relationship to the clinical observations of the total testing situation.