Saturday, October 24, 2009

High school & college attainment, and political leanings.

Our first set of scatterplots shows the relationship between high school and college education attainment, and how both of these do (or do not) correlate with political preferences, as measured by Obama's margin in the 2008 election.

The first scatterplot shows US states, by high school and college graduation rates. Intuitively, these are two variables that could assumed to be correlated. However, the trend is fairly weak: there are a cluster of states with low attainment in both high school and college (most of which are located in the South or Appalachia), but otherwise the trend isn't very strong. If you you look at the "USA" point, all of the states to the right and down of it are states with above average high school graduation rates, but below average rates of college attainment. Likewise, some states have the opposite pattern: California and New York being two of the most important. Also, notice at the very right of the diagram, Alaska and Wyoming have the two highest high school graduation rates.
Which brings us to our second point. There has been, at some points, conventional wisdom that Democratic candidates are more succesful with a better educated electorate. But the presence of Alaska and Wyoming over on the very right of the diagram makes one wonder if this correlation holds up for high school graduation rates.
This chart, which compares high school graduation rate (as measured in difference from the national average, a somewhat confusing trick I used to make the graph look better) to Obama's margin in the 2008 election, does not provide any obvious evidence that states with high high school graduation rates are more politically liberal. In fact, almost the opposite: the upperleft hand corner of the diagram shows that Utah, Alaska and Wyoming, three states with very high high school attainment are also some of the most conservative. Strangely enough, McCain's support seems to come in two clusters: mountain and prairie states with high high school attainment, and a group of southern and Appalachian states with low high school attainment. And then Oklahoma in the middle. Obama states seem to run the gamut.

This diagram seems to return us to our conventional wisdom: the states with the highest levels of college attainment also were the biggest Obama supporters. However, as with any real world data, this information is not always the stereotype engine it could be. Utah, Kansas and Hawaii all have very close levels of college attainment, and yet have very different politics. Another thing of interest is that there seems to be a number of low-college states that supported Obama, but the inverse is not true: there are not many high-college attainment states that supported McCain.

There are many conclusions and guesses to be made from this data, but I will leave that to the reader to determine. I should also point out that there are many caveats about trying to operationalize educational data, since graduation rates across states may not always mean the same thing.

The data for these scatterplots was taken from, and I tried to be accurate, but there may have been artithmatic or data entry errors. There are many other caveats I could make, but according to my cat I have to go to bed.

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