The Equivalence Of Psychotic Syndromes Across Two Media

Abstract

The study goal was to test the equivalence of ten dimensions of psychotic behavior across two measuring media. The data consisted of ratings of 814 newly admitted schizophrenics made in the interview and on the ward. The factored. A least squares solution of a hypothesis matrix yielded ten clear factors of which eight were defined both by ward and interview measures.

A multimethod factor analysis of behavioral and objective measures of psychopathology.

“…The two analyses provide considerable support for the convergent and discriminant validity of nearly all of the 10 psychotic syndromes measured by the IMPS. Results of the first analysis of the two method sources, interview and ward behavior, agree well with the findings of an earlier study (Lorr & Cave, 1966). In that study, a hypothesis-testing procedure was applied to 38 interview items taken from the IMPS and 42 ward behavior items taken from an earlier form of the PIP.…”

Multimethod factor analysis in the evaluation of convergent and discriminant validity.

“…The interdependence of content and method components has an almost universal effect when traditional factor-analytic methods are applied to intercorrelation matrices based upon measures from widely different domains. As others have noted (Lorr & Cave, 1966), factors typically emerge which are specific only to a given method of measurement. Thus, to mention a few examples from what is a very long list, Norman (1968), while recognizing the many difficulties involved, nevertheless explored traditional procedures by intercorrelating a set of scores representing five traits measured by both questionnaire methods and by peer ratings.…”

A multimethod validation of the Inpatient Multidimensional Psychiatric Scale with chronically institutionalized patients.

“…Unfortunately, drug outcome studies have typically failed to provide data on the relationship of the IMPS to other criterion measures (e.g., Goldberg, Mattson, Cole, & Klerman, 1967), or have reported limited validity data only in narrowly circulated government publications (Klett, 1961). Several studies (Lorr & Cave, 1966;Lorr, O'Connor, & Stafford, 1960;Mefferd, 1968) have found significant relationships between IMPS scores and scores on a ward rating scale-the Psychotic Reaction Profile (PRP) (Lorr et al, 1960); however, the latter relationships are partially confounded by considerable item overlap between the two scales. Only two studies to date have reported concurrent validity data on the IMPS with completely independent modes of assessment: Lorr and Hamlin (1971) found significant convergent correlations between the IMPS and several objective tests of psychomotor speed, vocabulary, etc., as well as the PRP; Paul et al (1972) found significant convergent correlations between the IMPS and itemindependent ward ratings and structured interview scores.…”