If today's health care environment can be described as a "living laboratory," then most industry experts would agree that payment models are the experiments.

The fee-for-service model that's served us for so long is being replaced with different models, ones that typically move some of the burden of risk from payers (and employers) to care providers. This transition, sometimes called "value-based payment," is intended to incentivize physicians and other health care providers to maintain a high quality of care as opposed to a high quantity of patients.

There are many different payment models operating in the marketplace, and each carries a different risk level for providers. New care delivery models or philosophies also emerging – patient-centered medical homes and accountable care organizations are two of the most prominent. Understanding how care models inter-relate – and how they are used in practice – will be increasingly vital as scientists in the living laboratory continue to develop hypotheses and test them.