Context: Medical assistants (MAs) employed in primary care practices are increasingly expected to perform new and more complex tasks, a phenomenon known as role expansion. In order to measure outcomes related to different job types, a standardized method to measure job roles is needed. Measuring and understanding MA job roles improves our ability to demonstrate the contribution of MAs to primary care teams. Objective. Pilot test a survey to characterize MA job roles using specific tasks performed and the presence or absence of role expansion. Study Design: Initial focus group and survey phase of exploratory sequential mixed methods design. Setting: One academic health system-affiliated primary care practice and one private primary care practice, both located in metropolitan regions of Colorado. Population studied: MAs employed in primary care practice settings (N=9). Instrument: Semi-structured focus group protocol, pilot survey. Outcome Measures: Overall Job Satisfaction scale (three items), single-item job burnout measure, characteristics of MA job roles. Results: Comparing tasks performed by MAs in two practices revealed that MAs employed in both the settings reported regularly performing at least one task described in existing literature as part of an expanded MA role, though medical scribing was more prevalent in the academic health system practice and care coordination was reported more frequently by MAs employed in the private practice. Input from MAs showed the importance of interpersonal support both inside and outside of the workplace and care team structure (e.g. MA-to-clinician ratio). The utility of role expansion, tasks performed, and other job characteristics as predictors of employee outcomes will be explored.