Brewer, D. D., Potterat, J. J., Garrett, S. B., Muth, S. Q., Roberts, J. M., Jr., & Rothenberg, R. B. Comparison of direct estimate and partner elicitation methods for measuring the number of sexual and drug injection partners. Poster presented at the 126th annual meeting of the American Public Health Association, November 16, 1998, Washington, DC.

The number of sexual and injection partners is a key variable in HIV/STD epidemiology and risk assessment.  The most common method for measuring the number of partners is the direct estimate, in which subjects simply estimate the number of partners for a given period.  To evaluate the reliability of the direct estimate, we compare it with the partner elicitation approach, in which individual partners are elicited and then counted.  In two studies of persons at high risk for HIV in Colorado Springs (n = 462)  and Seattle (n = 113), subjects responded to both direct estimate and partner elicitation questions.  We examine the correlations and mean differences between the numbers of partners derived from each method.  For the Seattle study, we also compare the test-retest reliability of the two approaches, compare estimates for both approaches with estimates of the number of new partners scaled-up from the test-retest partner elicitation data, and describe subjects’ comments on how they produced their direct estimates.  This research provides a detailed assessment of the reliability of the direct estimate procedure and suggests appropriate interpretations of direct estimate data.