Short answer: kids' test scores do tend to dip over summer, on average. How big the dip is, and who it hits, is a real argument among researchers.
Every May, the summer slide warnings start showing up: workbooks, camps and apps that promise to stop it. Before you buy anything, it helps to know how much kids actually lose over summer. The researchers don't agree, and the reasons they disagree are worth knowing.
The short version
The study everyone builds on is a 1996 review of 39 studies on summer vacation. The authors combined the 13 most recent and found that test scores fell over summer by about one month on a grade-level scale, or about a tenth of a standard deviation. Math took a bigger hit than reading, and math computation and spelling took the biggest. The loss also grew as kids got older (Cooper et al., 1996).
Two other details from that review are worth knowing. Middle-class kids seemed to gain on reading recognition tests over summer, while lower-income kids lost ground. And the authors guessed at why math slips more: facts and procedures, like times tables and spelling patterns, are forgotten more easily than ideas, and there are more chances to read over summer than to do math.
A long study in Baltimore pushed the idea further. Researchers followed children from first grade into high school. They found that most of what kids gained came during the school year, but that the gap between higher- and lower-income kids by ninth grade traced mostly back to different summers in elementary school (Alexander, Entwisle & Olson, 2007). That's where the popular line "summer explains most of the achievement gap" comes from.
The catch with both: the data is old. The 1996 review covers studies from before then, and the Baltimore children it followed into college are long since grown. Tests, summers and schools have changed.
This is the part most summer slide warnings leave out. A 2019 paper argued that a lot of what people "know" about summer learning loss was bent by the measuring itself (von Hippel & Hamrock, 2019). They pointed to two problems, here in plain words:
When they corrected for those problems, using the Baltimore study's data and two others, the most consistent result was that gaps between kids form mainly in early childhood, before school starts. After that, most gaps grew little, and some shrank. On whether gaps grow faster during school or during summer, they called the evidence inconsistent.
Another team redid a well-known 2004 study, "Are Schools the Great Equalizer?", using better test scores on its data and on a newer group of kids (von Hippel, Workman & Downey, 2018). The differences between kids were already large at the start of kindergarten and actually shrank over the next two to three years. The spread between kids still tended to grow in summers and shrink during school years, which suggests school helps even things out. But after kindergarten the changes were small and didn't show up the same way across grades, subjects or groups of kids.
So these papers don't say summer slide is a myth. They say the old story was too tidy, and that the biggest differences between kids show up before kindergarten, not over summer.
The newest work uses huge datasets from one testing company, NWEA, which makes the MAP Growth tests. One researcher looked at 3.4 million students and found that summer slide was common but not inevitable. The kids who lost the most over summer tended to be the ones who'd gained the most during the school year. The data also didn't line up well with the usual explanations, like access to summer programs (Kuhfeld, 2019). That piece is a short magazine article for educators, not a full research paper, so it's worth holding a little more loosely.
Another study using NWEA data found the same thing in more detail: kids vary enormously. Some kept learning over summer at their school-year pace. Others lost nearly everything they'd gained that year. Race and family income explained only about 4% of the differences in summer loss, a surprise given the classic story. And in English language arts, 52% of students lost ground in all five summers the study followed (Atteberry & McEachin, 2021).
One limit: these datasets all come from the same company's test, and the second team says itself that the measurement concerns above are a reason to revisit the older findings.
Here's an honest summary, from a team that isn't made of researchers:
One more thought, and this is a guess, not a finding: a lot of "loss" in September might be rust, given the 1996 review's point that facts fade faster than ideas.
The research doesn't point to one fix, so here are options that are cheap, low-pressure and backed by something. Every family is different; pick what fits.
A review of 41 summer reading programs for kindergarten through eighth grade found that kids who took part improved on reading measures compared with kids who didn't. That included home programs built around kids picking and reading their own books. The benefits were larger for programs with solid reading instruction, and for kids from low-income families (Kim & Quinn, 2013). These were organized programs, not just a reading log on the fridge, so it's worth not stretching the finding. But a library program is free, and the kids get to choose.
Many public libraries use themes and reading logs from a nonprofit called the Collaborative Summer Library Program, which started in 1987 when ten Minnesota library systems teamed up on a shared summer program (CSLP). Try asking at your library's desk in May.
If math facts and spelling are what slip most, that's where a few minutes here and there is a reasonable place to start. Practice spread over days sticks better than the same amount crammed together. That's mostly shown in adults (Cepeda et al., 2006), but small studies found it in fifth graders learning vocabulary (Sobel, Cepeda & Kapler, 2011) and in 5- to 7-year-olds learning science (Vlach & Sandhofer, 2012). Trying to recall an answer, instead of rereading it, also helps it stick, and that held in a study of kids around 10 (Karpicke, Blunt & Smith, 2016). There's more on that in does quizzing help kids learn?
In practice, that can be a handful of math questions on a car ride, or a quick spelling round while dinner cooks. Car trivia counts too. It's practice, and nobody calls it that.
The American Academy of Pediatrics' report on play says play with parents and other kids builds attention and self-control, language and social skills (Yogman et al., 2018). The report means hands-on, mostly unstructured play, and it warns about screens crowding that out. So apps don't really count as play here. The backyard, building forts and board games on a rainy afternoon do. A family game night covers a lot of this at once.
Watch for practice turning into a daily negotiation. If a workbook page a day becomes a fight, one option is a few minutes that feel like a game instead. Every family is different, and some kids love workbooks.
Mostly yes, on average. A 1996 review found test scores fall over summer, more in math than reading. But later researchers showed that some older findings were inflated by how tests were scaled and switched between spring and fall. Kids also vary a lot: some keep learning over summer and some lose much of the year's progress.
The classic estimate is about one month of school, on average, with math facts and spelling slipping most. Newer data from millions of students shows that average hides a wide range. Some kids hold steady while others lose nearly a full year's gains. The average tells you little about one particular child.
No one has a sure fix for every child. Low-pressure options with some research behind them include a library summer reading program, a few minutes of math or spelling practice spread over the week, and lots of play with family and friends. Short and frequent tends to beat long and crammed.
They can. A review of 41 summer reading programs for kindergarten through eighth grade found kids improved on reading measures compared with kids who didn't take part. Benefits were largest for low-income children and for programs with solid reading instruction. These were organized programs, so a reading log alone may do less.
About this article. The Super Trivia Kids team wrote this from the published studies listed below. We're not researchers, teachers or doctors, and every source links to the original so you can check our reading of it. The summer learning research is genuinely disputed, so we've tried to give both sides and say where the data is old, small or from a single test.
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