The answer is not necessarily, but sometimes, or it's complicated, according to a Boston Globe review of extended day programs in Boston schools.
While a few schools did see a rise in test scores after adding time to the school day, many others did not. Still others seemed to find that gains are difficult to maintain over time. A few schools have ended their extra hours or may do so in the future.
Despite this, Boston Public Schools are considering new proposal to add 40 minutes to the school day in more than 50 schools, at a cost of $12.5 million a year.
Is 40 minutes enough to make a difference? That's unclear. Just as results seemed to vary depending on the school, the length of time varied as well. At one school 30 minutes seemed to make a difference, but a full hour at another school did not.
What is clear is that extended day programs tend work better when they are well planned and well executed. And supporters point out, they also increase opportunities for enrichment and the arts.