This report published by the Center for Healthcare Research & Transformation analyzes the variation in quality of healthcare by region in Michigan.

From the report:

For more than 20 years, researchers at Dartmouth Institute for Health Policy and Clinical Practice have been sharing data on regional variation in the use of health care services: variation that does not seem to be explained by health status or other relevant differences among the populations studied. Most of work done on geographic variation has been done on the Medicare population, and some could argue that the phenomenon of variation is unique to a senior population or some specific attribute of the Medicare structure. However, just over 10 years ago, we in Michigan were fortunate to have the opportunity to collaborate with our colleagues at Dartmouth to look at this same kind of data in the commercial Blue Cross and Blue Shield of Michigan (BCBSM) population1. Our findings then showed that patterns of geographic variation in the commercial population were similar to those found in the Medicare population.

Full Report: Health Care Variation in Michigan (PDF | 1.56 MB)