Results from the Early Head Start Research and Evaluation Project—another randomized controlled trial, this time of the birth-to-three program—showed much the same thing. In a 2013 analysis by Cheri Vogel and colleagues, parents with access to Early Head Start were 6 to 7 percentage points less likely to spank their two- and three-year-old children than parents who had applied to Early Head Start but had been randomly denied. Early Head Start also increased immunization rates and improved family functioning overall; parents with access to Early Head Start were more likely than parents in the control group to teach and read to their children, to enforce a regular bedtime, and to be engaged rather than detached during play. Analysis of Head Start Impact Study data by Alexander Gelber and Adam Isen similarly finds that Head Start increases parents’ positive interactions with their children, including how much time they spend with them in educational activities.