Background and Purpose: The Norbeck Social Support Questionnaire (NSSQ) provides a rich portrait of one’s perceived social support including network size/composition and quality of support. Analyses of quantitative research reports and critiques of the NSSQ revealed non-negligible measurement error. We document evidence of measurement error, report potential sources of this error, and present forthcoming psychometric testing. Methods: Quantitative evidence of measurement error from the NSSQ literature provided the basis for initial hypotheses concerning sources of error in network nomination and support ratings. We then conducted cognitive interviews to investigate these hypotheses. Results: Cognitive interviews revealed evidence of respondents’ miscomprehension and response option bias. Conclusions: The current nomination process coupled with the lack of a “not applicable” response option and embedded examples in tangible Aid items reduces the accuracy of NSSQ subscores.