Harmonization of Cognitive Performance Measures across Five European Countries: Results from the Survey of Health, Ageing and Retirement in Europe – Harmonized Cognitive Assessment Protocol

BACKGROUND: Understanding the structure and measurement validity of cognitive instruments administered across settings is an important prerequisite to cross-national comparative research on cognitive aging. Characterizing the suitability of commonly used cognitive items for measuring variations among older adults across European countries warrants attention, given their cultural and linguistic diversity. METHOD: Using data from the Survey of Health, Ageing and Retirement in Europe – Harmonized Cognitive Assessment Protocol (n = 2,687), we employed psychometric methods to 1) assess model fit and potential measurement differences (differential item functioning) across five European countries (Czech Republic, Denmark, France, Germany, Italy); 2) estimate harmonized factor scores for general cognitive performance and specific cognitive domains (memory, executive functioning, visuospatial skills, language and fluency, and orientation); and 3) evaluate the reliability and criterion validity of the harmonized factor scores. RESULTS: Models had adequate to good fit to the data and there was little evidence of meaningful item bias, except in the language domain. The harmonized factor scores generally exhibited satisfactory reliability and good criterion validity, as indicated by correlations with age, educational attainment, and risk factors of dementia and cognitive impairment. DISCUSSION: Findings underscore the need to account for cultural diversity and language differences when conducting cross-national comparisons of later-life cognitive function in European countries. Estimated factor scores enable future harmonized research on cognitive aging in Europe.