AbstractThe intercorrelations of the sub‐tests of the Bellevue Adult Intelligence Scale, as given by Wechsler, are factorised by the centroid method and the solution rotated to a preferred ‘bi‐factor’ pattern. An interpretation is suggested involving a general eductive factor, a verbal comprehension factor, a spatial‐perceptual factor, and a memory factor. The various sub‐tests are evaluated in the light of the matrix, the ‘similarities’, ‘comprehension’, and ‘block designs’ standing out well. The adequacy of the test as a whole, and of the component scales, is considered; and it is finally concluded that caution must be exercised in giving diagnostic significance t