Tracking Down a Learning Gap

A learning gap is a missing prerequisite: a skill earlier in the sequence that never quite settled, so everything built on it wobbles. A student who never understood place value will struggle with long division, and a child who still sounds out words letter by letter will fall behind in comprehension however hard they work at grade-level texts. Re-teaching today's lesson more slowly rarely fixes this, because today's lesson is not where the problem is. The useful job is finding the missing piece and teaching that, and parents can do most of the finding at home with the student's own work. (Matching lessons to a "visual" or "auditory" learning style is not part of it: a 2008 review by Harold Pashler and colleagues found no adequate evidence that such matching improves learning.)

1. Collect the evidence. Gather three or four recent tests, quizzes and homework sheets in the subject that is causing trouble, ideally marked and dated. A single grade tells you almost nothing; the wrong answers are where the information is.
2. Sort the mistakes into patterns. The same error across different problems, such as writing 1/2 + 1/3 = 2/5 every time, points to a conceptual gap rather than carelessness. Correct setups with wrong arithmetic (7 x 8 = 54) suggest number facts that are not yet automatic, and many blank answers usually mean the student did not know how to begin. Errors that are random and inconsistent are a different signal, more often linked to rushing, fatigue, anxiety or attention.
3. Probe one level down, then another. Write three or four short questions on the skill just beneath the one that is failing, and keep stepping back until the student answers quickly and accurately. That point is the last solid skill. Short spoken questions work better than a full worksheet, and the school's own screening data (a reading fluency check, for example) can save you a step.
4. Teach the gap directly. Spend the time on the missing skill itself, with concrete examples, before returning to the current topic. Tell the teacher what you found; they may be able to give the student targeted practice in class, which keeps home and school working on the same thing.
5. Make it stick with retrieval and spacing. A 2013 review by John Dunlosky and colleagues rated practice testing and spaced practice as the two most useful study techniques they examined. In practice, that means quizzing rather than rereading, and opening each homework session with two or three mixed review problems on the repaired skill for several weeks.
6. Know when to ask for more. If months of well-targeted help produce little progress, or the same difficulty shows up across subjects and years, request a formal school evaluation in writing. Our separate guide to IEPs, 504 plans and school evaluations explains that process.

Here is how steps 2 and 3 play out with a ninth-grader stuck on equations. Her quiz shows that she cannot solve 3x + 5 = 20, and her wrong answers are inconsistent from one problem to the next, so she is not following a single faulty rule. Asked to solve x + 5 = 20, she gets 15, but slowly and by guessing numbers until one fits. Asked why subtracting 5 from both sides keeps the equation true, she has no answer and says she was told to "move the 5 over". She does know that 20 minus 5 and 15 are the same amount. The gap, then, is not two-step equations at all. It is the idea of the equals sign as a balance between two equal quantities, which she has been working around with memorised moves since about sixth grade. Ten minutes with a drawn balance scale, followed by a week of short daily problems where she writes what she did to each side, is a better use of time than another worksheet of two-step equations.

What the research says about closing gaps

Gaps are more widespread than they were a few years ago. The 2022 National Assessment of Educational Progress (NAEP), the federal benchmark often called the Nation's Report Card, recorded a 5-point drop in 4th-grade maths and an 8-point drop in 8th-grade maths compared with 2019, the largest maths declines since those assessments began in 1990. Reading scores fell 3 points in both grades. The next round, released in early 2025, showed little overall recovery. Students who were in early elementary school during the 2020 and 2021 disruptions may have missed foundations that only cause trouble years later, so the step-back probing in step 3 may need to go further than you expect.

The intervention with the strongest evidence for closing gaps at scale is what researchers call high-dosage tutoring: sessions several times a week or daily, groups of one to four students, a consistent trained tutor, and time during the school day rather than optional slots after it.

The best-known example comes from Chicago. The University of Chicago Education Lab studied a maths tutoring model developed by Saga Education, in which ninth- and tenth-graders worked with a tutor in pairs for one class period every day. Two large randomized trials, reported by Jonathan Guryan and colleagues, found gains in maths test scores of roughly 0.2 to 0.4 standard deviations, along with fewer failed maths courses. That is a large effect for high school students, an age at which many interventions show little.

A 2020 review of 96 randomized trials of tutoring by Andre Nickow, Philip Oreopoulos and Vincent Quan reached a broadly similar conclusion. Tutoring produced substantial average gains, and the strongest results came when sessions took place during school and were run by teachers or trained paraprofessionals.

If you are weighing a paid tutor, ask whether they will begin with a diagnostic of their own and how often they will report what they found. A tutor who starts on this week's homework without checking the skills underneath it is repeating the approach that did not work the first time.