Construct validity of the Work Productivity and Activity Impairment questionnaire across informal caregivers of chronically ill older patients

Value Health. 2009 Sep;12(6):1011-7. doi: 10.1111/j.1524-4733.2009.00542.x. Epub 2009 Apr 23.


Objectives: To assess the validity of the Work Productivity and Activity Impairment questionnaire as adapted for caregiving (WPAI:CG) to measure productivity loss (hours missed from work, impairment while at work, and impairment in regular activities) due to unpaid caregiving for medically complex older adults.

Methods: The WPAI:CG was administered along with the Caregiver Strain Index (CSI) and Center for Epidemiologic Studies Depression Scale (CESD) to a caregiving population (N = 308) enrolled with their older, medically complex care-recipient in a cluster-randomized controlled study. Correlation coefficients were calculated between each productivity variable derived from the WPAI:CG and CSI/CESD scores. Nonparametric tests for trend across ordered groups were carried out to examine the relationship between each productivity variable and the intensity of the caregiving.

Results: Significant positive correlations were found between work productivity loss and caregiving-related strain (r = 0.45) and depression (r = 0.30). Measures of productivity loss were also highly associated with caregiving intensity (P < 0.05) and care-recipient medical care use (P < 0.05). The average employed caregiver reported 1.5 hours absence from work in the previous week and 18.5% reduced productivity while at work due to caregiving. Employed and nonemployed caregivers reported 27.2% reduced productivity in regular activities in the previous week.

Conclusion: The results indicate high convergent validity of the WPAI:CG questionnaire. This measure could facilitate research on the cost-effectiveness of caregiver-workplace interventions and provide employers and policy experts with a more accurate and comprehensive estimate of caregiving-related costs incurred by employers and society.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Validation Study

MeSH terms

  • Absenteeism*
  • Activities of Daily Living
  • Aged
  • Caregivers / psychology*
  • Caregivers / statistics & numerical data
  • Chronic Disease / psychology
  • Depressive Disorder / etiology
  • Depressive Disorder / psychology
  • District of Columbia
  • Efficiency*
  • Female
  • Humans
  • Male
  • Maryland
  • Middle Aged
  • Quality of Life
  • Randomized Controlled Trials as Topic
  • Sickness Impact Profile*
  • Stress, Psychological / etiology
  • Surveys and Questionnaires / standards*
  • Workplace / psychology*