Most federal social programs have never been evaluated for true effectiveness. The good news is that they are ideally situated for just such study.
Health, education, welfare ... the federal government spends more than $630 billion annually on hundreds of social programs. How many of them work? No one knows. And that's a problem.
Most federal programs have never been evaluated for true effectiveness. And most evaluations that are conducted – and there are many – aren't worth the paper they're written on. They may examine a national program only locally, or lack a "control group" to compare against.
The best way to determine whether such programs work is to conduct large-scale, multisite, experimental evaluations. These studies should use random assignment to compare results of people assigned to programs with those in similar circumstances but not assigned to the programs.
The good news is that federal programs are ideally situated to accommodate such evaluations. The bad news: The federal government has conducted only 13 such evaluations since it began to study itself in the 1960s.
Maybe the Feds just don't want to be purveyors of bad news. That's certainly what emerged from the 2010 Head Start Impact Study. A rigorous experimental evaluation, the study placed almost 5,000 children eligible for Head Start into two treatment conditions, determined by a lottery. Children who won the lottery got access to prekindergarten Head Start services; the others either didn't attend preschool or found alternatives to Head Start.
The study tracked the children's progress through kindergarten and the first grade. Overall, the program yielded little to no positive effects. On all 41 measures of cognitive ability, Head Start failed to raise abilities of those who entered the program as 4-year-olds. Specifically, their language skills, literacy, math skills, and school performance were no better than those of the children denied access to the program.