Bech's Clinical Psychometrics
Per Bech: Clinical Psychometrics.
Wiley-Blackwell A John Wiley & Sons Ltd. Publication,
Oxford 2012. (202 pages)
The Danish original of this monograph was published by Munksgaard, Copenhagen, Denmark in 2011 with the title Klinisk psykometri.
INFORMATION ON CONTENTS: “Clinical Psychometrics” is divided into ten parts, including the “Introduction,” “Summary and perspectives” (part 9), and the last part (part 10) with the title “Who is carrying Einstein’s baton?” Part 1, deals with “classical psychometrics” (Kraepelin, Spearman, Hotelling, Eysenck); part 2 with “modern psychiatry - DSMIV/ICD-10”; part 3 with “modern dimensional psychometrics” (Fischer, Rasch, Siegel, Mokken); and part 4 with “modern psychometrics – item categories” (Likert, Overall, Cohen). From the remaining four parts in three, “the clinical consequences of IRT (item response theory) analysis” is discussed, and in one (part 8), the possibility of using “questionnaires” as “blood tests” is addressed. From the three parts which deal with the “clinical consequences of IRT analysis,” one (part 5) is dedicated to the “pharmacopsychometric triangle,” another (part 6), to “health related quality of life,” and the third, to the “concept of stress.” The volume is complemented by a “glossary,” “appendices,” “references” and an “index.”
AUTHOR’S STATEMENT: The central concept of this book is the “Pharmacopsychometric Triangle” in which (A) covers the desired clinical effect of a drug, (B) the unwanted, or side effects produced by the drug, and (C) the patient-reported quality of life as a balance between (A) and (B), covering the “mental dimension of health.”
The measurement-based care, as evaluated by the “Pharmacopsychometric Triangle,” is in this book discussed within the frame of reference to brief clinically and psychometrically valid scales where the total scores are “sufficient statistics.” “Effect-size” (response) and “number needed to treat” (remission) are two other important statistics.
From a pure psychometric point of view it is the “item response theory model,” and not “factor analysis” that is recommended for showing that the summed total score of a brief scale is a “sufficient statistic.” The item response theory model provides descriptions of the difficulty to rank order each individual item in a scale to secure by addition a total score.
This is the first book that identifies by the “item response theory model” the valid scales for measuring the effects of “antipsychotic,” “antimanic,” “antidepressant” and “antianxiety” activity of drugs within the “Pharmacopsychometric Triangle.” The author was first, in the late 1970s to introduce the “item response theory model” in clinical psychiatry.
In the Appendix of this book Max Hamilton’s lecture from 1977 on the clinical validity of depression scales is presented. It was one of Hamilton’s most important presentations that have never been published internationally. The Appendix also includes illustrations of both, the “item response theory model” and “principal component analysis.”