Does Head Start work?

Finally, it looks as if someone in the government is trying to seriously measure the impact of its many programs, like Head Start

 ... to determine if access to Head Start caused better developmental and parenting outcomes ..., the study randomly assigned Head Start applicants either to a Head Start group that was allowed to enroll, or to a “control” group that could not.

Here is what they found:

·       ..., the advantages children gained during their Head Start and age 4 years yielded only a few statistically significant differences in outcomes.

Professor Esther Duflo, who advocates such randomized trials to evaluate policy, has been appointed to the administration policy council.  Will she recommend policy changes based on the science?