The study would be done by either historians or social scientist from major universities and you would be hard pressed to find a more liberal group of people in the entire country than either one of those two. As such the rigorous test would slant towards what they believe a president should do and to ensure Kennedy came out somewhere very near the top. Once the test is invalid the whole study will be crap. The left would celebrate it and the right would dismiss it as another case of liberals using taxpayer money to create test to prove they are smart.