[Interpretation of changes in BOP (Evaluation Scale for Elderly Patients) in longitudinal studies of individual patients].

This study describes test-retest data for the BOP, a Dutch Geriatric Rating Scale which has been modeled upon the Stockton Geriatric Rating Scale. This so called BOP (Beoordelingsschaal voor Oudere Patiënten) contains 35 items pertaining to six aspects of the patient's daily behaviour on the ward: helplessness, aggressiveness, physical disability, depressive behaviour, mental disability and inactivity. These six aspects (subscales) were derived from factor analysis. Normative data, inter-rater reliability and validity have been determined for Dutch samples of elderly patients in nursing homes and psychiatric hospitals. Since 1971 the BOP is used extensively in Holland and Belgium. In this study test-retest correlation coefficients could be computed for 556 patients from four different psychogeriatric nursing homes. The correlations between test and retest over an interval of three months were for the six subscales resp.: .91, .68, .88, .59, .81 and .83. By determination of the standard error of measurement, statistical norms could be developed to estimate the significance of individual change, for example in experimental studies of single cases.