D.C. summer school switches to invitation only School officials told Frazier that he is too far behind, she said. The District's summer program for elementary- and middle-school students used to be open to everyone on a first-come, first-served basis. Officials have reconfigured the program to target lagging readers, a strategy meant to maximize limited resources and reach students who are likely to benefit the most from the five-week program. But there's a trade-off: The new summer program is not designed to meet the intensive needs of students who are most profoundly below grade level. That leaves out Frazier's grandson and hundreds of other struggling D.C. children. "Because of the numbers of struggling students that we have, from just below grade level to many years below grade level, there are always going to be students who need support who aren't going to be able to get it from this program," said Dan Gordon, the school system's deputy chief for academic programming. We're not at the point where we can run summer school for everyone. Volumes of research have shown that summertime learning matters, especially for poor children. With less access to enriching out-of-school experiences, poor children tend to lose more academic ground than their middle-class peers during the languid summer months, exacerbating the achievement gap with every passing year. That so-called summer slide is part of a broader literacy problem in the District. Fewer than half of D.C. children are proficient in reading, according to standardized tests, and more than a third of all city residents are functionally illiterate, according to a 2007 report. Some charter schools have lengthened their academic years or adopted year-round calendars to stop the summer slide. And several D.C. public schools run their own summer programs, paying for them out of the school budget or with the help of grants. But the school system doesn't have the resources to offer summer help to every child who needs it, Gordon said. The school system's central office is spending about $2.4 million this year - or about one-third of 1 percent of its $800 million budget - on summer programs for general-education students in kindergarten through 12th grade. In 2012, those programs served 3,750 students, according to budget documents submitted to the council. Invitation-only admission helps concentrate those scarce resources on students who truly need extra help, Gordon said. Officials selected students who scored within a certain range on reading assessments, a tactic meant to identify those most likely to benefit from summer programs. Some struggling readers, particularly in middle school, were not invited because they scored too high. But many students were excluded because they scored too low. Those students are so far behind that they need more intensive help - such as one-on-one instruction - than the summer program is designed to provide, Gordon said.