Development of a rating scale for primary depressive illness.

This is an account of further work on a rating scale for depressive states, including a detailed discussion on the general problems of comparing successive samples from a ‘population’, the meaning of factor scores, and the other results obtained. The intercorrelation matrix of the items of the scale has been factor-analysed by the method of principal components, which were then given a Varimax rotation. Weights are given for calculating factor scores, both for rotated as well as unrotated factors. The data for 152 men and 120 women having been kept separate, it is possible to compare the two sets of results. The method of using the rating scale is described in detail in relation to the individual items.