title: Note on the Relation between the Power of a Significance Test and the Reliability of the Measuring Instrument.
abstract: The relation between the power of a significance test in a block design with correlated measurements and the reliability of the measuring instrument has been the subject of a debate in the literature. This relation is further analyzed in terms of the components of variance entering the reliability coefficient and the noncentrality parameter. The function relating the true scores of alternative measuring instruments is considered. Power and reliability are positively related for linearly related true scores, and the relation is indeterminate, permitting on inverse relation for nonlinearly related true scores. The relevance of the distinction between the reliability study and the treatment study is discussed.
authors.forename: J
authors.initials: J
authors.lastname: Levin