Visualization of data is great. And sometimes it tells us something...though we don't always know what. Slate has an interactive feature showing the rise of diabetes in America by county. Nothing too surprising.
But follow the gradient from El Paso to the Illinois-Missouri border. The differences are small across state lines, but the consistent differences along the borders really don't make. Are there state-level policies or regulations causing this? Or, are there state-level differences in measurement? This weird pattern shows up in other CDC data I've seen. Update: I think the mystery is solved in the comments:
Very interesting. I suspect the answer has to do with the manner in which the county estimates are produced. I went to the original data source, the CDC, and then to the relevant FAQ: http://apps.nccd.cdc.gov/DDT_STRS2/FAQ.aspx#countylevelestimates There they say that the diabetes prevalence estimates come from the "CDC's Behavioral Risk Factor Surveillance System (BRFSS) ...
