The American ideal of lazy summers filled with fun has an unintended consequence: If students are not engaged in learning over the summer, they lose skills in math and reading, says Jeff Smink, vice president for policy for the National Summer Learning Association, for the New York Times. Summers off are one of the most important, yet least acknowledged, causes of underachievement in our schools.  Decades of research confirm that summer learning loss is real. According to a report released last month by the RAND Corporation, the average summer learning loss in math and reading for American students amounts to one month per year…