KastorFlowUpdated October 17, 2026
AI for studying: what the research says
Which kind of AI helps you learn, by the numbers.
The research favors AI that makes you practice over AI that answers for you: unrestricted ChatGPT cut later exam scores by 17%, while a structured AI tutor more than doubled learning gains. Spaced practice and practice testing are the strongest study methods measured. A source-grounded notebook such as Gemini Notebook (formerly NotebookLM) fits that evidence: it answers from your own material, cites it, and makes flashcards and quizzes.
We make KastorFlow, a Chrome extension for Gemini Notebook. The studies on this page aren't ours; each number links to its source.
94%
of UK undergraduates use generative AI for assessed work (1,054 surveyed)
−17%
exam scores for students who practiced with unrestricted ChatGPT, once access ended (about 1,000 high school students)
Over 2×
median learning gains with a structured AI tutor against an active-learning class, in a median 49 minutes (194 Harvard students)
d = 0.85
spaced practice, the most effective of 10 study techniques measured across 242 studies
d = 0.74
practice testing, second; rereading scores 0.47 and summarizing 0.44
18%
of GPT-4's academic citations were fabricated; 55% for GPT-3.5
How well 10 study techniques work
Higher is better. Source: Donoghue & Hattie, Frontiers in Education 2021, 242 studies.
What that means for an AI study tool
| What the research shows | What to look for | Gemini Notebook | KastorFlow adds |
|---|---|---|---|
| Unrestricted AI answers lowered exam scores 17% | Makes you answer before it explains | Flashcards and quizzes from your sources | A saved tutor prompt that asks first and hints before answering (free, 10 prompts) |
| Spaced practice is the strongest method (d = 0.85) | Brings material back over days and weeks | No spaced review schedule | Sends new flashcards to Anki for spaced review (1 a month free; no limit on Pro) |
| Practice testing is next (d = 0.74) | Turns material into questions | Quiz and Flashcards in Studio | Downloads every Studio artifact at once (free) |
| GPT-4 fabricated 18% of its citations | Answers only from sources you chose, and shows where | Every answer cites your sources | Builds a notebook on a topic from Gemini Notebook's own research (free: 5 a month) |
| A structured AI tutor more than doubled gains | Follows your course, not random questions | Chat, Audio and Video Overviews on your sources | Adds a whole lecture playlist in one go (free: 3 runs a month) |
How to study with AI, based on the research
- Put one course in one notebook: slides, readings and lecture videos. KastorFlow adds a whole YouTube playlist at once.
- Ask with a tutor prompt that makes you answer first (the one below), not with "explain this".
- After each topic, make Flashcards and a Quiz in Studio and answer them without looking.
- Review the flashcards spaced over days and weeks. KastorFlow sends them to Anki (1 a month free; no limit on Pro).
- Before you use a claim, open the passage it cites.
A tutor prompt to copy
Be my tutor for these sources. Ask me one question at a time about the topic I name. Wait for my answer, then tell me what I got right, give a hint if I'm wrong, and cite the passage. Don't give the full answer until I've tried twice.
Paste it into Gemini Notebook's chat, or save it in KastorFlow's prompt picker to reuse it in any notebook (free, 10 prompts).
KastorFlow adds these steps to Gemini Notebook. Free to install, no account needed.
Add to ChromeSources
- HEPI Student Generative AI Survey 2026
- Bastani et al., PNAS 2025
- Kestin et al., Scientific Reports 2025
- Donoghue & Hattie, Frontiers in Education 2021
- Walters & Wilder, Scientific Reports 2023
Checked October 17, 2026. Download every number with its source (CSV) · CC BY 4.0
Use these numbers
Quote any number with a link to this page. Suggested credit: KastorFlow, “AI for studying: what the research says,” https://kastorflow.com/stats/ai-for-studying-statistics, updated October 17, 2026.
Questions
What is the best AI tool for studying?
For studying your own course material, a source-grounded notebook such as Gemini Notebook (formerly NotebookLM) fits the research best: it answers only from your sources, cites them, and turns them into flashcards and quizzes, the study methods with the strongest evidence. Add spaced review, for example KastorFlow sending the flashcards to Anki, and a tutor prompt that asks questions instead of giving answers.
Does using AI improve grades?
It depends on how it is used. In a 2025 field experiment, students who practiced with unrestricted ChatGPT scored 17% lower on exams once access ended, while students using a tutor that gave hints instead of answers did about as well as students without AI. In a Harvard trial, a structured AI tutor more than doubled median learning gains.
Is NotebookLM good for studying?
Yes, for studying your own material. Gemini Notebook, formerly NotebookLM, answers only from the sources you add, cites them, and makes flashcards, quizzes and Audio Overviews. It does not schedule spaced review; that needs a flashcard app such as Anki.
Which study method works best?
Spaced practice (d = 0.85) and practice testing (d = 0.74) were the most effective of ten techniques in a 2021 meta-analysis of 242 studies; rereading (0.47) and summarizing (0.44) were among the weakest.