This information is for reference purposes only. It was current when produced and may now be outdated. Archive material is no longer maintained, and some links may not work. Persons with disabilities having difficulty accessing this information should contact us at: https://info.ahrq.gov. Let us know the nature of the problem, the Web address of what you want, and your contact information.
Please go to www.ahrq.gov for current information.
Figure 5. Definition of Medical Service Area (MSA) Based on Patient Origin: Commitment Index (CI)
A choroplethic or shaded map (bottom) is used to display numeric information (top). This example gives a graphic depiction of hospital admissions from the hospital's perspective; shaded portions indicate the ZIP Code areas that contribute the first 60 percent of the hospital's patients.
Return to Text