Agreement between head of household informant and self-report in a community survey of substance use in India.

This survey of 500 households in a New Delhi urban slum compared reports of substance use by the head of the household informant with individual self-report. Information from the two sources was compared for 1,132 people above the age of 15 years. The paired agreement regarding the use of substances was high (kappa=0.92; S.E.=0.01, z=92.0). The agreement regarding the presence of symptoms and classification of dependence for the use of alcohol, tobacco and opiates ranged from good to excellent and head of household reports had a high positive predictive value for the use of these substances. This method provides useful estimates of drug use and dependence for substances associated with observable physiologic withdrawal syndromes, and is less costly and quicker to perform than traditional self-report methodologies.