Abstract: This report summarizes the findings from a research project designed to evaluate questions on social networks, HIV risk and exposure, as well as knowledge and use of post-exposure prophylaxis (PEP) or pre-exposure prophylaxis (PrEP) for the National HIV Behavioral Surveillance System (NHBS). The NHBS is conducted in three revolving cycles, which target three groups that are identified as being at high risk for HIV: Heterosexuals who are at high risk (HET); Men who have sex with men (MSM); and Injecting drug users (IDU). To recruit participants for the HET and IDU cycles, the NHBS uses respondent-driven sampling, which is a chain-referral sampling strategy. Information of respondents’ networks is collected during the survey to determine sample weights. The NHBS survey sponsor was interested in the validity of data produced from measures of network size and characteristics. In particular, do respondents consider similar types of people when reporting on their networks? Additionally, sponsors were interested in how respondents interpret and respond to measures regarding their knowledge and use of PEP and PrEP in the prevention of HIV. Other measures on the NHBS were evaluated in this study; however priority was given to questions which measured these particular constructs. This evaluation is based on three rounds of cognitive interviews that were conducted by the Questionnaire Design Research Laboratory (QDRL) at the National Center for Health Statistics (NCHS). Cognitive interviewing is a qualitative question evaluation method used to evaluate the validity of survey questions (Willis 2005; Miller 2011). The main goals of the project were to: 1) assess respondents’ interpretation of the survey questions and 2) identify any potential question response problems that could lead to response error in the survey data. The project was funded by the National Center for HIV, Hepatitis, STD, and TB Prevention (NCHHSTP), Division of HIV/AIDS Prevention (DHAP). The following report summarizes the cognitive interviewing methodology and describes how data analysis was conducted. An overview of the findings is then presented, followed by a question by question review of the findings.