As the notion of value-based payment has taken hold in the health care market – the concept that health care providers should be paid according to the quality of care they offer, as opposed to today's "fee-for-service" payment method – insurers, from the Centers for Medicare & Medicaid Services to commercial payers, have had to define and measure quality and value in health care.

And how those quality metrics are defined and collected, and how the payment measures are structured, vary from payer to payer – and even within different insurance organizations – as they experiment with various models to test what's most effective.

"Every payer has different metrics and different methods of payment," says Dr. David Nace, vice president of clinical development and medical director at McKesson. "That's the wild cowboy market economy we're in, and we need to move toward alignment."