After a significant slowing of activity earlier in the decade, the addition of primary, specialty group practices or both to hospital and health system investment portfolios is re-emerging as a potentially powerful tool to expand services, gain or sustain market share and manage costs. Hospitals have learned some valuable lessons during the past few years. Many hospital-medical group relationships that faltered in the late 1990s and the early part of this decade did so in part because institutions guaranteed physicians higher compensation as incentives to join their systems. Now, hospitals are finding ways to compensate based on productivity. The planning process begins by performing independent due diligence on the group, including a thorough review of the organization's financial status to know what they are getting into from a monetary perspective. The best time to make changes depends on the volume of work and the skills and competencies of existing staff including how easily, and for how long, they can handle broadened responsibilities and additional workloads.