Concurrent validity of a brief self-report Drug Use Frequency measure.

This study examined two sources of concurrent validity information for a brief Drug Use Frequency (DUF) measure--the well-validated Timeline Followback (TLFB) measure and knowledgeable collateral informants (i.e., spouses)--for 106 male alcoholic patients and their female partners (treatment sample couples) and for 130 male and female participants without current alcohol/drug problems (community sample couples). Results showed generally good concurrent validity of self-reported frequency of illicit drug use on the DUF. Treatment sample results showed high correlations (a) between patient self-reported frequency of drug use on the DUF and on the TLFB for all drug types and (b) between self- and collateral reports on the DUF for male patients and their female partners for the most commonly abused drugs (cannabis, cocaine, and heroin). Community sample results showed (a) high correlations between self- and collateral reports on the DUF for male and female participants for frequency of cannabis and cocaine use and (b) average percent agreement of 99% for all drug types on whether or not male and female participants had used each drug.