Item response bias was present in instrumental activity of daily living scale in Asian older adults

Item response bias (also called differential item functioning, DIF) in Instrumental Activities of Daily Living (IADL) occurs when members of different groups possessing the same disability level do not have the same probability of responding positively for a given item(s). This study aimed to identify the extent of DIF by gender, age, ethnicity, and dementia groups in IADL estimates in Asian (Chinese, Malays, and Indian) elderly subjects.