Abstract
Extraction of a difficulty component from a set of dichotomous items. We present here an application of de method proposed by Lawley and MaxweIl for the extraction of a difficulty component. This method was applied over a correlation matrix obtained from a set of dichotomous items. Comparisons between principal component analysis obtained from the original matrix and from the residual matriz seems closely similar, but in the first analysis a component emerges roughly similar to a difficulty component. Further research seems necessary to be done.
