Test administrator effects on cognitive performance in a longitudinal study of ageing

In longitudinal studies, changes in participants’ cognitive performances can partly be attributed to variations in the testing situation (testing specific factors), such as, different test administrators or different testing environments. Focusing on test administrator influence, testing specific factors were examined in a Swedish longitudinal study of ageing. Test scores from 6,686 examinations revealed significant test administrator effects on all instruments measuring speed of processing, episodic memory and spatial ability. 1.4–3.5% of the total variation in test scores was explained by the factor attributed to the test administrator. Further, results indicated task familiarity on speed scores, and fatigue attributable to the time of day of the testing session for memory and spatial ability. Participants tested in the testing centre performed significantly better than participants who received home visits. This study provides evidence that testing specific factors are tangible concerns in longitudinal ageing studies. Subjects: Neuropsychology; Cognitive Psychology; Cognitive Neuropsychology; Behavioral Psychology; Developmental Psychology