Statistical model: Higher black turnout in runoff was worth 10 points to Cochran

We can do more with these regressions, though. We can hold the African-American percentage of the population variables constant in both the Cochran and McDaniel regressions, while adjusting the non-African American variables. This process mirrors on a county level what would happen if white or traditionally Republican turnout went up but black or traditionally Democratic turnout didn’t change from the first to the second round. In my scenario, I kept the African-American turnout constant from the first round of voting, but let the white vote increase as it actually did.

The result: Cochran loses a lot of votes. Instead of Cochran winning the runoff by 2 points, or about 6,000 votes, he loses by a little less than 8 points, or about 25,000 votes. He drops about 40,000 votes from his 190,000 vote total, while McDaniel loses only about 15,000 from his 185,000 vote total. You can see this phenomenon in the chart below. It shows how much Cochran’s vote percentage against McDaniel would drop in each of Mississippi’s 82 counties (each county is one dot) if we keep black turnout on the county level the same from the first round of the primary to the runoff…