Understanding the behaviors and attitudes of at-risk populations is fundamental to controlling the spread of HIV, the virus that causes AIDS. The problem of nonresponse among these populations, however, plagues survey research designed to address these issues. Previous work undertaken to map out the dynamics of nonresponse--both noncontacts and refusals--have primarily focused on exploring the effectiveness of a single method of outreach. This analysis improves on this prior research by comparing the effectiveness of two types of outreach strategies in a follow-up face-to-face survey of individuals seeking HIV prevention services in New Jersey during the period 1999-2001. Case workers from community-based organizations (CBOs) attempted to contact one set of respondents, whereas "outsider" researchers attempted to contact the second set. In brief, the authors find that in contrast to a CBO research affiliation, an outsider researcher status is associated with higher survey response rates. (Contains 4 tables.)