Date of Award


Degree Type


Degree Name

Master of Science (MS)



Committee Chair(s)

Glendon Casto


Glendon Casto


The Bayley Scales of Infant Development (Bayley, 1969) is the most widely used infant assessment instrument in the United States. Reasons for its widespread use include research into the nature and development of intelligence, studies of intervention efficacy, and treatment and placement of handicapped infants.

To this date, the stability and predictive validity of the Bayley scales have not been well established. According to Webster and Bates, "There remains a serious lack of research examining the stability of all general intelligence measures over extended intervals of time" (1977, p. 5). Anastasi (1976) suggests that tests like the Bayley are particularly useful for the early detection of neurological or sensory defects. Conversely, Caldwell concluded that tests given in infancy describe very well but are inadequate at diagnosis.

Bayley (1958) claimed that the use of infant tests for research in human development is appropriate and justified, despite 1 ow predictive validity. Cronbach (1967) noted that correlation matrices involving infant measures follow a simplex pattern (value highest near the major diagonal, decreasing uniformly with distance therefrom) and are therefore useless for factor analyses of qualitative stages of mental development. Lewis and McGurk (1972) did not find a simplex pattern of correlations in their study, but argued that infant tests should not be used to assess intervention efficacy. 11 Simply stated, infant intelligence scales are unsuitable instruments for assessing the effects of specific intervention strategies11 (Lewis & McGurk, 1972, p. 1176).

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