Natural experiments are terrific -- if you can plan ahead or have the resources to quickly take advantage of one as it occurs. This study does just that, finding that people who received information from the Social Security Administration gained more knowledge and had more confidence in Social Security than people who did not receive the information. And this includes statistical controls for such predictors as age, education, race, and gender.
The study, published in a recent The Journal of Politics, includes a neat structural equation model for those who like pretty pictures and smoke-and-mirrors statistical analyses to arrive at an interesting conclusion, that knowledge leads to confidence. And not the other way around.
Oh, and Happy New Year.