The 60-second card
The finding
What students already know is one of the biggest factors in what they can read and learn next. A planned sequence of science, history, and the arts from kindergarten raises reading scores years later.
Do this
Teach a planned, content-rich sequence from K onward. Use reading time to build knowledge in connected units, not random passages chosen to practice a skill.
Best evidence
A lottery study of nine Colorado charter schools using Core Knowledge: students who won a kindergarten seat scored about 16 percentile points higher in reading in grades 3–6 than applicants who lost (Grissmer et al.(opens in a new tab)).
+16 percentile points
in reading, grades 3–6, in a lottery study
The 5-minute brief
Why it works
Reading comprehension depends on knowing what the text is about. A student who knows a lot about weather understands a passage on storms and learns more from it, so knowledge snowballs. Skills-only reading time ("today we practice finding the main idea") doesn't build the knowledge that comprehension runs on.
Two independent studies
- Core Knowledge lottery study. Because seats were assigned by lottery, winners and losers were comparable at the start. At the one school in a low-income district, effects were large enough to close the income gap (EdWorkingPapers(opens in a new tab)). This is the first experimental study of a knowledge-building curriculum's long-term effects.
- MORE randomized trial. In 30 schools and nearly 3,000 students, thematic science and social studies lessons in grades 1–2, plus summer reading on the same themes, improved science reading comprehension (effect size 0.18). Gains were strongest on passages that used vocabulary taught in the lessons (Kim et al.(opens in a new tab)).
What it looks like
| Grade band | In practice |
|---|---|
| K–2 | Six-week read-aloud units on topics like the human body or early American history, with key vocabulary taught directly. |
| 3–5 | Reading lessons and science lessons share a topic, so students read, write, and talk about the same content. |
| 6–8 | History and science classes assign substantial reading in the subject, not just textbook summaries. |
| 9–12 | Background is taught before analysis; students read primary sources once they know the story. |
Common mistakes
- Cutting science and social studies time to add more reading skills practice.
- Choosing texts by reading level alone, with no connection between one week's topic and the next.
- Expecting quick gains. The lottery study's effects built up over years.
What a leader looks for in 5 minutes
- Is the reading lesson about something students will keep learning about next week?
- Are science and social studies being taught at their scheduled times in K–5?
What we don't know yet
The lottery study compares charter enrollment, so the curriculum and the school model come as a package. In the federal review of the MORE trial, the overall district reading score did not improve significantly, though a reading comprehension subtest did (WWC(opens in a new tab)). Effects on social studies and science scores themselves are less studied.
Go deeper
- Researcher
- David Grissmer; Daniel Willingham; James Kim
- Translator
- Natalie Wexler, The Knowledge Gap; E.D. Hirsch
Also called: background knowledge, content-rich curriculum, knowledge-rich curriculum, Core Knowledge
Grades and subjects
Sources
- EdWorkingPapers (opens in a new tab)
edworkingpapers.com
- Kim et al. 2023 (MORE) (opens in a new tab)
cepr.harvard.edu
- Grissmer et al. 2023 (opens in a new tab)
educationnext.org
- WWC review of MORE (opens in a new tab)
ies.ed.gov