Summary
Two problems concerning the IMPS are revealed. First, the importance of an appropriate reliability measure is demonstrated in a sample of 124 inpatients. Widely divergent results are found using three different intraclass correlation coefficients. The one producing the highest results was used by Klett and McNair (1966) and by Behrends et al. (1971). However, the results from this measure only apply to certain types of investigation. A measure more applicable to most investigations in psychiatric research (the intraclass correlation coefficient of individual ratings with between-rater variance included) produced results that were clearly lower, although still acceptable, with an average correlation of 0.72 between the 12 scales. Secondly, the multiplication of item scores by 2 or 8 when forming the scale scores is shown to lead to unusual and undesirable scale distributions in a sample of 1932 inpatients. The resulting implications for assessing change scores on some of the IMPS scales are discussed.
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References
Bartko JJ (1966) The intraclass correlation coefficient as a measure of reliability. Psycholog Rep 19:3–11
Bartko JJ, Carpenter WT (1976) On the methods and theory of reliability. J Ner Ment Dis 163:307–317
Behrends K, Flegel H, Helmchen H, Hippius H, Höfften KD, Schacht L, Schulte PW (1971) Quantifizierung psychotischer Symptome unter transkulturellen Aspekten. Soc Psychiatr 6:66–72
Bender W (1976) Studie zur Reliabilität und differentiellen Validität der Lorr-Skala (IMPS). Unpublished Dissertation, Hamburg
Cohen J (1968) Weighted kappa: nominal scale agreement with provision for scaled disagreement or partial credit. Psychol Bull 70:213–220
Degckwitz R, Helmchen H, Kockott G, Mombour W (1971) Diagnosenschlüssel und Glossar Psychiatrischer Krankheiten: ICD (International Classification of Diseases). 8th Revision. Deutsche Ausgabe der Internationalen Klassifikation der WHO und des Internationalen Glossars. Springer, Berlin Heidelberg New York
Ebel RL (1951) Estimation of the reliability of ratings. Psychometrika 16:407–424
Helzer JE, Robins LN, Taibleson M, Woodruff RA, Reich T, Wish ED (1977) Reliability of psychiatric diagnosis: I. A methodological review. Arch Gen Psychiatr 34:129–133
Jacobi P (1974) Untersuchungen zur Faktorenstruktur, Zuverlässigkeit und Gültigkeit einer deutschen Bearbeitung der IMPS nach Lorr. Unpublished Dissertation, Hamburg
Klett CJ, McNair DM (1966) Reliability of the acute psychotic types. In: Lorr M (ed) Explorations in typing psychotics. Pergamon Press, Oxford London New York, pp -
Lissitz RW, Green SB (1975) Effect of the number of scale points on reliability: A Monte Carlo approach. J Appl Psychol 60:10–13
Lorr M (ed) (1966) Explorations in typing psychotics. Pergamon Press, Oxford London New York
Lorr M, Klett CJ (1967) Manual for the inpatient multidimensional psychiatric scale (IMPS); revised. Consulting Psychologists Press, Palo Alto, Calif.
Lorr M, Klett CJ (1968) Major psychotic disorders. Arch Gen Psychiatr 19:652–658
Mattel MS, Jacobi J (1971) Is there an optimal number of alternatives for Likert scale items; Study I: Reliability and validity. Educ Psychol Measurement 31:657–674
Mariotto MJ, Farrell AD (1979) Comparability of the absolute level of ratings on the Inpatient Multidimensional Psychiatric Scale within a homogeneous group of raters. J Consult Clin Psychol 47:59–64
Mariotto MJ, Paul GL (1974) A multimethod validation of the Inpatient Multidimensional Psychiatric Scale with chronically institutionalized patients. J Consult Clin Psychol 42:497–508
Mombour W (1972) Verfahren zur Standardisierung des psychopathologischen Befundes. Teile 1 und 2. Psychiatria Clin 5:73–120; 5: 137–157
National Institute of Mental Health (1978) Handbook of psychiatric scales, (2nd ed). Preston & Assoc, Inc, Rockville, Maryland
Remington M, Tyrer PJ, Newson-Smith J, Cicchetti DV (1979) Comparative reliability of categorical and analogue rating scales in the assessment of psychiatric symptomatology. Psychol Med 9:765–770
Sarris V, Lienert GA (1974) Konstruktion und Bewährung von klinisch-psychologischen Testverfahren. In: Schrant WJ, Baumann H (Hrsg) Klinische Psychologie. Huber, Bern, S 286–351
Spitzer RL, Fleiss JL (1974) A re-analysis of the reliability of psychiatric diagnosis. Br J Psychiatr 125:341–347
Wing JK, Cooper JE, Sartorius N (1974) Measurement and classification of psychiatric symptoms. An instruction manual for the PSE and Catego program. University Press, Cambridge
Zerssen D von, Möller H-J (1980) Psychopathometrische Verfahren in der psychiatrischen Therapieforschung. In: Biefang S (Hrsg) Evaluationsforschung in der Psychiatrie: Fragestellungen und Methoden. Enke, Stuttgart, S 121–166
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This investigation was supported in part by a grant from the Deutsche Forschungsgemeinschaft
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Cairns, V., Faltermaier, T., Wittchen, H.U. et al. Some problems concerning the reliability and structure of the scales in the Inpatient Multidimensional Psychiatric Scale (IMPS). Arch Psychiatr Nervenkr 232, 395–406 (1982). https://doi.org/10.1007/BF00345596
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DOI: https://doi.org/10.1007/BF00345596