A 2015 study found that US elementary school students were getting too much homework. Education leaders determined the amount of homework that was adequate for each grade level. More than 1,000 parents of children in kindergarten through grade 12 participated in the study. They answered questionnaires about how much time their children spent on homework. The researchers found that children in the first grade had up to three times the recommended homework load.
Read more about this 2015 study and the correlation between homework and stress.