Comments left by participants in the margins of a survey are commonly ignored during data analysis. Rather than overlook these marginalia, we describe a qualitative analysis of the notes, underlines, and cross-outs left by participants in the margins of the Female Sexual Function Index (FSFI; Rosen et al., 2000). Participants who were diagnosed with late stage breast cancer had taken the FSFI as part of a larger multimethod quality of life study. In our analysis, we identify 3 categories to analyze the 136 instances of marginalia left next to FSFI items: clarifications, corrections, and noting items as “not applicable.” Using these marginalia as guidance, we developed a modified scoring procedure for the FSFI that accounted for those participants who marked items as “not applicable” in their marginalia but would have been dropped from analysis due to missing data. We offer guidelines for researchers interested in analyzing marginalia as a means to incorporate and amplify participant feedback in survey research design. This is especially important when even well-validated instruments are used to make, for example, clinical diagnoses and treatment decisions, but do not adequately account for participants’ lives. Studies of marginalia enable qualitatively derived insights to be effectively incorporated into survey methodology, enabling us to better attend to the ways participants communicate and share their lives with us over the course of any study.