OBJECTIVES: To evaluate clinicians’ ability to understand and respond to the IGA-LCL, a single item severity rating scale of LCLs at neutral facial position. METHODS: Individual face-to-face cognitive interviews were conducted with seven dermatologists and one plastic surgeon from the US with experience in aesthetic medicine including treating LCLs.  Participants attended one of two research sessions.  At each session, the participant group received training on the IGA-LCL, consistent with the training provided for clinicians in phase 3 trials using the IGA-LCL. Two researchers then conducted individual semi-structured interviews with participants, following a process that required them to “think aloud” while reading response options and formulating a response.  Interviews were audio-recorded and transcribed. Analyses summarized participant feedback on the instrument. RESULTS: Overall, findings indicate that the IGA-LCL scale is clear and easy to use. Clinicians understood the content and were able to use the response options as intended. No revisions to the IGA-LCL scale were recommended based on results from this study, though training topics were identified for further emphasis and clarification. A few participants suggested alternate text for some response descriptions though these same participants understood and could use the descriptions as currently stated. One participant noted that she might arbitrarily define the descriptions differently based on her clinical experience and noted the subjectivity in making a clinical judgment of LCL severity, but understood and could use the IGA-LCL appropriately based on the training.  Two participants indicated that they usually think about the “worst” length of wrinkle, but they could rate “average” length as instructed in the training. Most participants stressed the importance of training for proper use of the scale. CONCLUSIONS: Results support the content validity of the IGA-LCL. This research represents an important step toward establishing the content validity of the IGA-LCL relative to the FDA PRO Guidance.