BACKGROUND:In response to growing pressures on primary care, leaders have introduced a wide range of workforce and practice innovations, including team redesigns that delegate some physician tasks to nonphysicians. One important question is how such innovations affect care team members, particularly in view of growing dissatisfaction and burnout among healthcare professionals. We examine the work experiences of primary care physicians and staff after implementing Lean-based workflow redesigns. This included co-locating physician and medical assistant dyads, delegating significant responsibilities to nonphysician staff, and mandating greater coordination and communication among all care team members. METHODS:The redesigns were implemented and scaled in three phases across 46 primary care departments in a large ambulatory care delivery system. We fielded 1164 baseline and 1333 follow-up surveys to physicians and other nonphysician staff (average 73% response rate) to assess workforce engagement (e.g., job satisfaction, motivation), perceptions of the work environment, and job-related burnout. We conducted multivariate regressions to detect changes in experiences after the redesign, adjusting for respondent characteristics and clustering of within-clinic responses. RESULTS:We found that both physicians and nonphysician staff reported higher levels of engagement and teamwork after implementing redesigns. However, they also experienced higher levels of burnout and perceptions of the workplace as stressful. Trends were the same for both occupational groups, but the increased reports of stress were greater among physicians. Additionally, members of all clinics, except for the pilot site that developed the new workflows, reported higher burnout, while perceptions of workplace stress increased in all clinics after the redesign. CONCLUSIONS:Our findings partially align with expectations of work redesign as a route to improving physician and staff experiences in delivering care. Although teamwork and engagement increased, the redesigns in our study were not enough to moderate long-standing challenges facing primary care. Yet higher levels of empowerment and engagement, as observed in the pilot clinic, may be particularly effective in facilitating improvements while combating fatigue. To help practices cope with increasing burdens, interventions must directly benefit healthcare professionals without overtaxing an already overstretched workforce.