Surgical quality difficult to evaluate.

• Position: Health Insurance

Insurance providers face significant challenges in assessing the quality of individual surgeons' patient outcomes reliably and need better ways to measure physician quality when selecting the best surgeons for their members, according to a statistical analysis of more than 220,000 coronary artery bypass graft procedures performed during a recent 18-year-period. "Under the American managed care system, patients have little choice between providers for major surgeries, as most of us are limited to surgeons contracted by our insurance plans," explains physician Marco Huesch, assistant professor of strategy at Duke University's Fuqua School of Business, Durham, N.C., who conducted the analysis.

"While it might be natural to assume that health plans select surgeons based on the quality of their patient outcomes, as it turns out, it's generally almost impossible for an individual company to do so."

Huesch's analysis of rates on in-hospital mortality did find differences in outcomes among surgeons. However, it also confirmed that the "law of small numbers," a statistical term for a situation where there are too few items in a sample to draw reliable conclusions, would prevent insurers from assessing the quality of the surgeons' care accurately.

"While we found differences in mortality rates across...