Resources for teachers / sources
Sources
Every number in the talk “Fast Tools, Slow Thinking” and on these pages, with where it comes from and what year. They are grouped by slide, in the order of the talk. If you find a number that is not here, tell us.
The last column says how well a number was checked:
- Checked against the primary source
- Secondary report; not checked against the primary
- My own data or records; no outside check
- Counted from this site
- Well-known background; not re-checked
Numbers marked “my own data” come from my own records. The class numbers (finishing times, the rater, the questions) are from one graduate course of 12 students: they show what happened in one small class, not what would happen in yours. Found a mistake? Tell us and we will fix it in public.
Teens and AI
| Number | Source | Year | How checked |
|---|---|---|---|
| 54% of US teens used an AI chatbot for schoolwork (fall 2025)The vote choices in the talk (about 15%, about 35%, more than half) were guesses to vote on, not findings. | Pew Research Center, teens and AI | 2026 (survey fall 2025) | Checked against the primary source |
| About 1 in 10 teens (10%) do all or most of their schoolwork with a chatbot; 21% some; 23% a little | Pew Research Center, teens and AI (same report) | 2026 | Checked against the primary source |
Where I’ve landed
No outside numbers. These are my own conclusions.
This is where you work
| Number | Source | Year | How checked |
|---|---|---|---|
| Teachers work about 49 hours a week, around 10 over contract | RAND, State of the American Teacher | 2025 | Secondary report; not checked against the primary |
| Teachers spend about $895 of their own money a year | AdoptAClassroom, teacher survey (covers the 2024–25 school year) | 2025 | Checked against the primary source |
| 68% of teachers use AI detectors on student work | Center for Democracy & Technology, survey of teachers | 2023–24 | Secondary report; not checked against the primary |
| 22.6% of US students were chronically absent | AEI and Chalkbeat reporting on chronic absence (2024–25 school year) | 2026 | Checked against the primary source |
The answer just became free
| Number | Source | Year | How checked |
|---|---|---|---|
| Chegg’s revenue fell from $617.6 million to $376.9 million in one year, down 39% | Chegg, Form 10-K for fiscal 2025 | 2025 | Checked against the primary source |
| College students paid $341 a year for course materials in 2024–25, about half the $701 of 2007–08 | NACS (National Association of College Stores), Student Watch 2024–25 | 2025 | Checked against the primary source |
| Publishers’ higher-education revenue was $4.7 billion, up 8.5% | Association of American Publishers, StatShot annual report | 2025 | Checked against the primary source |
What we mean by AI
| Number | Source | Year | How checked |
|---|---|---|---|
| 354 lessons | Biochemistrypedia repository history and content (origin/main), counted October 23, 2026 at 6:35 pm ET | 2026 | Counted from this site |
How fast: 17 weeks, then 13 days
| Number | Source | Year | How checked |
|---|---|---|---|
| First commit June 12, 2026. The first 30 lessons took about 17 weeks (to October 10) | Biochemistrypedia repository history and content (origin/main), counted October 23, 2026 at 6:35 pm ET | 2026 | Counted from this site |
| 324 more lessons in 13 days (October 11 to 23) | Biochemistrypedia repository history and content (origin/main), counted October 23, 2026 at 6:35 pm ET | 2026 | Counted from this site |
| 354 lessons, all live, in 11 courses, with 464 films (lesson explainers, scientist profile films and methods films) | Biochemistrypedia repository history and content (origin/main), counted October 23, 2026 at 6:35 pm ET; films counted from the media manifest | 2026 | Counted from this site |
| Grade 7 Life Science: 34 lessons in 8 units (LS.1 to LS.11), planned and released on October 23 (first commit 11:40 am, last lesson merged 6:34 pm ET) | Biochemistrypedia repository history and content (origin/main), counted October 23, 2026 at 6:35 pm ET | 2026 | Counted from this site |
| High school Biology: 33 lessons (BIO.1 to BIO.8), all released October 20 | Biochemistrypedia repository history and content (origin/main), counted October 23, 2026 at 6:35 pm ET | 2026 | Counted from this site |
The 60-second film
| Number | Source | Year | How checked |
|---|---|---|---|
| 354 lessons in 11 courses, 464 short films (repeated from the film’s narration) | Biochemistrypedia repository history and content (origin/main), counted October 23, 2026 at 6:35 pm ET | 2026 | Counted from this site |
500 students wrote a book with me
| Number | Source | Year | How checked |
|---|---|---|---|
| Written with more than 500 students of UVA Biochemistry; 133 profiles of 190 scientists; free as PDF, EPUB and audiobook | The Molecule Hunters, deppmannlab.com/book (read October 23, 2026) | 2026 | Checked against the primary source |
What building taught me
No new numbers. 354 lessons is counted above.
Checking: 49 wrong, 453 imprecise
| Number | Source | Year | How checked |
|---|---|---|---|
| An AI fact-checker with web access read 3,468 claims in one course: 49 wrong, 453 imprecise, 287 it could not verify; 841 edits | My fact-check findings for the Cell Signaling course (44 lessons), 2026 | 2026 | My own data or records; no outside check |
| Wrong claims per lesson: 4.0 in the first batch (9 lessons), 1.5 in the next, 0.0 to 0.6 in Units 3 to 8 (about 0.3 on average). Said in the talk as "four a lesson at first, under one by the end" | My fact-check findings for the Cell Signaling course (44 lessons), 2026 | 2026 | My own data or records; no outside check |
| For Genetics, a second check by a different company’s model found 80 more corrections, for example a trisomy-21 DNA share corrected from 1.5% to 0.8% | Genetics course fact-check, second-opinion pass (repository commit bf4fc5b) | 2026 | My own data or records; no outside check |
| Expert review takes about 1 to 2 hours per lesson | My own estimate while reviewing the lessons; not a timed study | 2026 | My own data or records; no outside check |
Thursday: 2 finished, then 9
| Number | Source | Year | How checked |
|---|---|---|---|
| Pre-work module: 36 steps, about 3 to 4 hours for a careful student. Two of 12 students had finished by Thursday morning; by Friday 8:40 am, nine had and three were partwayOne small graduate class. Not a sample of any other group. | BIOL 7240 / PFN Foundations of Neuroscience I, University of Virginia graduate course, Fall 2026 (12 students, anonymized) | 2026 | My own data or records; no outside check |
| The “Room” slide: 2 of 8 students said yes, 6 said no, to whether blocking dynein proves TrkA is the cargo | BIOL 7240 / PFN Foundations of Neuroscience I, University of Virginia graduate course, Fall 2026 (12 students, anonymized) | 2026 | My own data or records; no outside check |
| One predict, argue, reveal cycle took 8 to 10 minutes in the room, not the 4 I had planned | BIOL 7240 / PFN Foundations of Neuroscience I, University of Virginia graduate course, Fall 2026 (12 students, anonymized) | 2026 | My own data or records; no outside check |
| Lineage of the idea: Just-in-Time Teaching (Novak and colleagues, 1999); formative assessment (Black and Wiliam, 1998) | Novak et al. 1999; Black and Wiliam 1998 | 1999; 1998 | Well-known background; not re-checked |
Predict: where they ranked
| Number | Source | Year | How checked |
|---|---|---|---|
| An AI rater’s depth scores tracked answer length (correlation 0.74). The student with the most time on the module ranked second from the bottom of 12My own rater, one course. A warning, not a finding, and not shown for K-12. "Time" is the sum of gaps under 45 minutes between a student’s saved answers, a rough measure. | BIOL 7240 / PFN Foundations of Neuroscience I, University of Virginia graduate course, Fall 2026 (12 students, anonymized) | 2026 | My own data or records; no outside check |
| AI-text detectors flagged 61% of TOEFL essays (written by non-native English speakers) as AI-written | Liang et al., Patterns | 2023 | Secondary report; not checked against the primary |
Questions nobody read
| Number | Source | Year | How checked |
|---|---|---|---|
| About a quarter (20 to 25%) of students’ own questions went beyond the lesson; 4 of 12 students asked about 70% of them | BIOL 7240 / PFN Foundations of Neuroscience I, University of Virginia graduate course, Fall 2026 (12 students, anonymized) | 2026 | My own data or records; no outside check |
Shift 1: The answer is free. The trail is the evidence.
| Number | Source | Year | How checked |
|---|---|---|---|
| Blue-book sales up 80% at Berkeley over two academic years | Wall Street Journal report on blue-book sales, as repeated in news coverage (May 2025). I did not see the original article | 2025 | Secondary report; not checked against the primary |
| Detectors flagged 61% of TOEFL essays as AI-written | Liang et al., Patterns | 2023 | Secondary report; not checked against the primary |
| 22% of answers were revised after the reveal | BIOL 7240 / PFN Foundations of Neuroscience I, University of Virginia graduate course, Fall 2026 (12 students, anonymized) | 2026 | My own data or records; no outside check |
Shift 2: Your students’ AI reads the lesson before they do.
| Number | Source | Year | How checked |
|---|---|---|---|
| Unguarded GPT-4: practice scores up 48%, later exam scores down 17% | Bastani et al., Proceedings of the National Academy of Sciences | 2025 | Secondary report; not checked against the primary |
| A guarded tutor did not show that harm; a Harvard tutor with guardrails doubled gains on two lessonsAll AI-tutor evidence is short-term and not yet replicated. | Kestin et al., Scientific Reports | 2025 | Checked against the primary source |
Shift 3: Materials are easy now. Your attention is the scarce thing.
| Number | Source | Year | How checked |
|---|---|---|---|
| Teachers who use AI every week save about 5.9 hours a week, mostly on preparation | Gallup and the Walton Family Foundation, teachers and AI | 2025 | Checked against the primary source |
| Just-in-Time Teaching, 1999 | Novak et al., Just-in-Time Teaching | 1999 | Well-known background; not re-checked |
One idea. Every level.
A 40-second film with no numbers. It shows one idea at six levels, from toddler to research lab.
Shift 4: Meet every student where they are.
| Number | Source | Year | How checked |
|---|---|---|---|
| Adaptive software that taught each student at their own level raised math scores 0.36 standard deviations and Hindi 0.22 after about 4.5 months (Mindspark, Delhi). The authors describe "very wide variation in student learning levels within a single grade" | Muralidharan, Singh and Ganimian, American Economic Review (NBER working paper w22923, abstract) | 2019 | Checked against the primary source |
| Teaching at the Right Level is a "Great Buy" | Smart Buys report, Global Education Evidence Advisory Panel | 2023 | Secondary report; not checked against the primary |
| A later review finds the effects heterogeneous and often modest | Ardington, Menendez and Thunde, review of Teaching at the Right Level | 2026 | Secondary report; not checked against the primary |
| A depth ladder with four steps (grade 7 Life Science, Biology, Biology II, College) on every high school Biology lesson, and a three-setting supports switch | Biochemistrypedia repository history and content (origin/main), counted October 23, 2026 at 6:35 pm ET | 2026 | Counted from this site |
Shift 5: Their questions become the curriculum.
| Number | Source | Year | How checked |
|---|---|---|---|
| Interest in science falls from about age 9 to 17 | Gottfried et al. | 2001 | Secondary report; not checked against the primary |
| Curiosity questions: about 2.4 per two hours in kindergarten, about 0.5 in grade 5 | Engel | 2011 | Secondary report; not checked against the primary |
When a measure becomes a target
| Number | Source | Year | How checked |
|---|---|---|---|
| Goodhart’s law: a statistical regularity tends to collapse once pressure is placed on it for control (UK monetary policy) | Charles Goodhart | 1975 | Checked against the primary source |
| "When a measure becomes a target, it ceases to be a good measure": the common wording, written about examination performance | Marilyn Strathern, p. 308 | 1997 | Checked against the primary source |
| A similar point about social indicators, including test scores | Donald Campbell. Sources date it 1976 to 1979, so the talk says "in the 1970s" | 1970s | Checked against the primary source |
| China’s imperial civil-service examinations ran from the Sui dynasty (early 600s) until 1905, about 1,300 years. The talk says "more than a thousand years" | General historical knowledge | 1905 | Well-known background; not re-checked |
Understanding is the only thing left worth grading
No new numbers. "More than 500 students" is sourced under the book slide.
It can go wrong
| Number | Source | Year | How checked |
|---|---|---|---|
| A course AI tutor lowered grades, most for first-generation studentsHold it loosely: it has not been through peer review. | Liu et al., EdWorkingPaper 26-1598 (University of Maryland trial; not peer-reviewed) | 2026 | Checked against the primary source |
| Free tools help the already-engaged most | Reich, on MOOCs | 2020 | Secondary report; not checked against the primary |
What I’d ask of any AI in a classroom
No numbers. The five commitments are my own.
Other numbers on the /teachers pages
| Number | Source | Year | How checked |
|---|---|---|---|
| A $10,000 grant request (July 2026) said $5,000 would buy three to five complete lessons. It was not selected, and the site was built anyway | AI Catalyst grant request, July 2026 | 2026 | My own data or records; no outside check |
| Model scores, token counts and narration costs in “How it’s built” | The project files named next to each figure on that page | 2026 | My own data or records; no outside check |
| Fact-check numbers in the do-it-yourself guide and in “How it’s built” (3,468 claims, 49 wrong, 453 imprecise, 287 unverifiable, 841 edits; about 4 wrong per lesson at first, under 1 later) | My fact-check findings for the Cell Signaling course (44 lessons), 2026 | 2026 | My own data or records; no outside check |