Diagnostic instruments must be relatively free from respondent burden and cost effective to administer whilst remaining faithful to the psychiatric nomenclature. It seems logical to develop short form alternatives to rather lengthy and complicated diagnostic interviews to facilitate large scale data collection. The current study examines one method, signal detection theory, for developing a short form interview based on the Composite International Diagnostic Interview version 3.0. The method was able to retain the smallest number of items to predict a lifetime and 30 day DSM-IV diagnosis for ten disorders. Concordance analyses between the full form and the short form modules, demonstrated an excellent level of agreement in the whole sample and various subsamples of the Australian population as well as in an international comparison sample of the U.S. population. The good concordance between the long form and the short form demonstrates the ability of signal detection theory to assist in the development of valid short forms, which could replace lengthy diagnostic interviews when the aim is to reduce respondent burden and overall research costs.