What people don't write about and discuss is that the average IQ of Democrats is lower than the IQ of Independents, Non-Voters and definitely lower than Republicans. Yes, categorically.
Here is the data on education which is highly correlated with IQ:
Not HS Grad College Grad & Post-grad
% of Democrats 32% 15%
% of Independents 22% 18%
% of Republicans 19% 23%
Here is the data on people who earn incomes over $75,000 which is also highly correlated to IQ:
Income under $75,000 over $75,000
% of Democrats 74% 26%
% of Independents 72% 28%
% of Republicans 57% 43%
Those are the facts. Many studies have been done on non-voters level of income and education; non-voters match independents exactly.
To recapitulate: The Republican average IQ is higher than non-voters and independents and all three are higher than the Democratic average IQ.
Proposed IQ/political affiliation test: take a fairly stable city (low population turnover) with a representative population, such as Fresno, California. Go back to the Elementary Schools IQ tests of the early 1980s and then track down the students and look at their current party registration. The whole project could be done without any one person knowing the actual connection of the IQs and the final party affiliation. One person keeps the key to the school data secret but passes on the names and addresses to the person who leads a team to find the people and determine their party registration. A final person puts the names into categories without identifying the categories and gives the material to the first person to match the original IQ data with the categories without ever revealing the secret name/IQ data.
Such a survey could cost upwards of several hundred thousand dollars, but it can be done and I am sure it will substantiate my claim in this blog that Republicans are the political cohort that has the highest average IQ.