Making assessment locally relevant: measuring functioning for maternal depression in Khayelitsha, Cape Town

We developed a locally relevant functioning assessment instrument (FAI) for pregnant women and mothers of young babies to complement a widely validated instrument-the World Health Organization's Disability Assessment Schedule (WHODAS) 12-item version. The FAI is an outcome measure in a randomised controlled trial on the effectiveness of a lay counsellor administered intervention for distressed pregnant women in Khayelitsha, Cape Town. Nine items most commonly reported by 40 pregnant women or mothers with young babies in qualitative interviews were selected for the instrument, with a 10th item 'Other'. The FAI was validated with 142 pregnant women and mothers in Khayelitsha. Analysis was conducted to assess internal reliability, exploratory factor analysis and convergent validity. The FAI had good internal reliability (Cronbach's alpha = 0.77) and the explanatory factor analysis showed a clear 3-factor solution, relating to domestic, childcare and social activities. The FAI scores showed floor effects, but were positively correlated with the two measures of functioning (WHODAS 2.0 and Washington Group Short Set). The FAI scores also correlated with the measure of depression (Edinburgh Postnatal Depression Scale-EPDS), reflecting increased functional limitations associated with increased depressive symptoms. The results show that the FAI has good internal reliability, and good convergent and construct validity as a measure of functioning for this context. This paper reports on the process of developing an instrument and highlights the importance of using instruments that are locally relevant to ensure accurate measurement of functional status.