What Is Summer Learning Loss? What the Evidence Shows

Definition: what is summer learning loss?

Summer learning loss is the decline, or the lack of growth, in academic skills that can happen while students are out of school for the summer. It is also called summer slide or summer setback.

The idea is simple. Researchers give children the same kind of test in spring and again in fall. If the fall score is lower than the spring score, that gap is called a loss. If the score barely moves, it is called a flattening, because the child would normally have kept growing during a school year. A 2017 Brookings review by David Quinn and Morgan Polikoff notes that scholars have studied the question since 1906, so this is not a recent worry invented by the internet.

What is the summer slide, in everyday words?

The summer slide is the everyday name for the same thing. Parents usually mean that a child comes back in September a little rusty, needing a few weeks to recover math procedures or reading stamina that were sharp in June. Researchers use the more careful phrase because the effect is an average across many children, and individual children can slide, stand still or even gain.

What causes summer learning loss?

Nobody has a complete answer. The simplest explanation is practice: for roughly ten weeks a child has fewer structured hours of reading, writing and math, and skills that are not used can fade. NWEA researchers suggest that reading holds up better than math because many children read outside school more often than they practice math, and that procedural math skills may fade faster. A second explanation, the so-called faucet theory described in the Brookings review, says that school turns on a steady flow of resources for every child, and that in summer the flow slows for children from disadvantaged families while continuing for advantaged ones. In an April 2026 NWEA review, Megan Kuhfeld and Andrew McEachin put it bluntly: the field cannot really explain why summer learning differs so much from one student to the next.

What research shows about summer learning loss

Older research found that students lose about one month of school-year learning over summer on average, with sharper declines in math. Newer NWEA data find a dip of roughly 10 to 30 percent of a typical year's math growth and almost no average change in reading.

Reading

The classic synthesis, a 1996 review by Cooper and colleagues described in the Brookings article, found that achievement scores declined over summer by about one month of school-year learning, and that income-based reading gaps grew, because middle-income students tended to improve in reading while lower-income students tended to lose ground. More recent evidence is milder. On NWEA's MAP Growth test, summer reading changes are essentially flat on average, within less than one RIT point in either direction. Studies built on a national sample of children who began kindergarten in 2010 to 2011 (ECLS-K:2011) find that learning slows after kindergarten and first grade but does not, on average, drop.

Math

Math is where the dip shows up most consistently. In April 2026 NWEA researchers Megan Kuhfeld and Emily Morton, using the 2025 MAP Growth norms, reported typical summer changes in math of about 2 to 7 RIT points, which they describe as roughly 10 to 30 percent of what students learn in a typical school year. The drop is largest in the elementary grades. The table shows the published averages.

Typical summer change on NWEA MAP Growth, in RIT points (negative means a drop)

Summer between	Math	Reading
Spring K to fall 1st	-2.0	+0.8
Spring 1st to fall 2nd	-5.2	-0.2
Spring 2nd to fall 3rd	-6.4	+0.8
Spring 3rd to fall 4th	-5.1	+0.1
Spring 4th to fall 5th	-6.0	+0.1
Spring 5th to fall 6th	-7.3	+0.1
Spring 6th to fall 7th	-4.0	+0.2
Spring 7th to fall 8th	-2.5	+0.6

How much do kids lose over the summer, in months?

The honest range is wide. Cooper's early review put the average at about one month. A study of students in grades 2 to 9 in a southern state, cited by Brookings, estimated losses of 25 to 30 percent of school-year learning. The ECLS-K:2011 sample, by contrast, showed little evidence of overall loss after kindergarten and first grade. Any single statistic you see quoted, whether it says two months or three, picks one study out of this spread.

Who is affected most by summer learning loss

Evidence points to lower-income students in reading and to students in the upper elementary grades in math, but the pattern is not consistent across studies. Students at the bottom of the distribution can lose more than a full year of typical growth.

The Brookings review and a 2011 RAND report on summer programs both describe summer loss as hitting children from lower-income families harder in reading, adding up year after year. NWEA's recent work complicates that picture. The April 2026 review says gaps between low-poverty and high-poverty schools do not consistently widen in summer, and that Black-white score gaps hold steady or narrow, depending on the test. A 2019 NWEA analysis of 3.4 million students found a different twist: the students with the biggest summer losses were often the ones who had made the biggest gains during the school year. The authors' conclusion was that summer slide is common but not inevitable.

Averages also hide spread. In the 2026 MAP Growth analysis, students at or below the 10th percentile of summer change lost the equivalent of more than a year's typical school-year gains in most grades, and the spread between children in the same grade is wide. Learning rates, the authors note, are more variable in summer than during the school year.

Is summer learning loss real? Debate and limits

Yes, in many datasets, especially for math, but the size is contested. Some researchers consider it a serious problem, others a modest one, and some findings have not replicated.

• The test matters. NWEA notes that drop sizes vary sharply across tests. Interim tests such as MAP Growth, Star and i-Ready show far larger summer drops than the national ECLS-K studies, so it remains uncertain whether the slide should be treated as a trivial issue or a serious challenge.
• Timing matters. The MAP Growth estimates assume spring testing around week 36 of the school year and fall testing around week 1. A test given earlier in spring or later in fall captures some school-year learning and shrinks the measured slide. If children learn a lot after the spring test, the slide is underestimated.
• Gap claims do not always hold. Whether summers widen inequality depends on the metric and test used. Brookings concludes that summer loss and gap growth occur, but not universally across places, grades or subjects.
• Replication is patchy. The April 2026 NWEA review says some findings often fail to replicate, even in recent data.

None of this means summer is irrelevant. It means the confident headline versions, such as "kids lose two to three months every summer", are simplifications of a more uneven picture.

What summer learning loss means for parents

Treat it as a reason to keep a little reading and math in the week, not as a reason to worry. The average dip is real in math and small in reading, and children vary a great deal.

A practical reading of the evidence: math deserves a light, regular nudge; reading mostly needs to stay enjoyable and frequent; and your own child's fall results, rather than a national average, are the best guide to what to work on. NWEA researchers make a similar point, recommending that teachers use fall test results instead of spring scores alone to plan instruction. For concrete steps, read how to prevent the summer slide.