Imputation of missing values within WHODAS 2.0 data collected from low back pain patients using the response function approach.

Construct validity is preserved. Problems regarding the compliance of the items with the target group still persist. When researchers encounter missingness in data collected with WHODAS 2.0, the response function can be usefully implemented to impute missing values to improve the reliability of disability level estimates.Implications for rehabilitationThe Turkish version of the 36-item WHODAS is reliable and valid for assessing health and disability status in patients with low back pain.A critical issue is a systematic nonresponse was highly observed in items related to "work/school life activities" which are allowed to be skipped and excluded from the scoring according to WHODAS 2.0 training manual.Imputation of missing values within four items of "work or school activities" in domain 5 using the response function approach showed satisfactory reliability for the estimation of disability in adults with low back pain.This study showed missing data imputations with response function can be implemented by a statistician as contribute to a missing data management process better tailored to clinicians' interpretations.