This study compares the performance of IQCODE in understanding objective cognition across the U.S., England and India. It reports strong associations between IQCODE and objective cognition at low cognitive functioning in the U.S. and England. In India, however, the IQCODE was less sensitive to impairments at the lowest levels of cognitive functioning, particularly among those with no education. Informant characteristics may differentially impact informant reports across countries. Researchers should consider the use of country-specific adjustments to the IQCDOE scoring based on informant characteristics to improve cross-national comparability.
