Performance tests in human psychopharmacology (3): Construct validity and test interpretation

Abstract

The content. criterion and face validity of human performance tests in psychopharmacology research were examined in an earlier paper. Most evidence on test meaning and interpretation, however, comprises construct validity. This is critically scrutinized here, through a brief analysis of human performance theory (Broadbent, Sanders, Sternberg), and taxonomies of human performance function (Fleishman, Holding). While much construct evidence is rather nebulous and untestable (non-disprovable), it is probably the most accurate representation of current views on performance assessment. Tests gradually fall out of favour (or) into favour, rather than being shown to be clearly invalid (or) valid. Factor analysis, and task discrimination, are, however, two procedures for placing test interpretation/meaning on a sounder empirical basis. Returning to the overall problem of how best to investigate test validity. several proposals are made. Further criterion information should be sought, in large-scale studies, designed specifically to compare the practical utility of different tests and test batteries. There needs to be greater atmosphere of critical debate on test meaning, in order to clarify the performance functions being assessed. Factor analysis and task discrimination procedures also need to be more widely employed. Lastly, although many tests can be seen as measures of 'information processing', the inference that they provide indices of 'real-life performance', can rarely be made on current evidence.

A Double-blind, Placebo- and Flurazepam-controlled Investigation of the Residual Psychomotor and Cognitive Effects of Modified Release Zolpidem in Young Healthy Volunteers

“…Subjects were required to substitute each digit with a different nonsense symbol, according to a key printed at the top of the sheet which indicated the nonsense symbol that corresponded to each digit. The test involves the recognition and recoding of sensory information and has been described as a measure of simple information processing 37 and of psychomotor performance. 38 It also assesses visuomotor coordination, sustained attention, and concentration skills.…”

Human Cognition Assessment in Drug Research

“…The reader is referred to reviews of antidepressant- [54], antipsychotic- [55,56], anxiolytic- [57], hypnotic- [58] and antihistamine effects on cognition and psychomotor performance [59]. The issues of psychometric assessment discussed in this article also apply in this area of research [46][47][48].…”

“…Parrott outlined the requirements for performance tests in human psychopharmacology: reliability and standardisation [46], content validity, criterion validity and face validity [47], construct validity and test implementation [48]. Sensitivity to psychoactive drug effect is also an important prerequisite for tests in this area, although traditionally it is not in itself considered as an index of validity.…”

Prevention of relapse and recurrence of depression: newer versus older antidepressants

“…mianserin, trazodone) have been shown to cause more impairment than the newer antidepres sants (including lofepramine) in laboratory tests of cognitive and psychomotor function (Hindmarch et al, 1992). The older tricyclics have also been shown to cause impairment in driving tests, whereas SSRIs, reversible inhibitors of monoamine oxidase A (RIMAs) and nefazodone cause little or no impair ment (Louwerens et al, 1986;Raemaekers et al, 1994 Although these findings support the use of the newer drugs for long-term treatment, the predictive validity of psychomotor tests has been questioned (Parrott, 1987;Freeman & O'Hanlon, 1995).Many skilled tasks can be performed without undue effort and with spare processing capacity left available, and it has been suggested that information-processing tasks are measures of competence (potential) rather than actual performance (Parrott, 1991).…”