Oak National Academy
Oak National Academy's Aila lesson assistant saves primary teachers about 49 minutes a week in a randomised trial
In a ten-week randomised trial run by the NFER for the Education Endowment Foundation, English primary teachers who used Oak National Academy's AI lesson assistant Aila spent about 2.5 hours a week preparing lessons, against 3.3 hours for a comparison group. Resource quality was no worse, but teachers used Aila for only about 7% of lessons.
Key figures
Copied exactly from the sources. Copy any figure with its citation.
around 2.5 hours per week
Weekly time spent preparing lessons and resources by teachers in the Aila group (ten-week trial, autumn term 2025)1
3.3
hours per week
Weekly time spent preparing lessons and resources by teachers in the non-Aila comparison group1
0.8
hours (or 48.6 minutes) per week
Average weekly saving for the Aila group compared with the non-Aila group1
76%
Time spent by the Aila group as a share of the time spent by the non-Aila group1
What it took
The problem
Primary teachers in England spend many hours a week planning lessons and making resources. Nearly every teacher in the trial found lesson planning stressful and felt it took too much of their time. Oak National Academy is a public body that provides free curriculum resources, and it wanted to know whether its AI lesson assistant really cuts that workload without hurting quality.
What they built
Aila is Oak's AI lesson assistant. A teacher gives a lesson objective, and Aila drafts curriculum-aligned lesson materials grounded in Oak's own content. It launched in beta in 2024 and is free to use after creating an Oak account. The sources do not say which model it used during the trial.
How they did it
The Education Endowment Foundation asked the NFER to run a school-randomised controlled trial. Schools were randomly assigned. The Aila group was encouraged to use the tool for ten weeks in autumn 2025, and the comparison group was asked not to use it. Both groups could use other AI tools. In total, 464 Key Stage 2 teachers (Years 3 to 6) from 108 schools took part. Independent assessors reviewed the resources teachers produced.
Results
Teachers in the Aila group spent around 2.5 hours a week on lesson and resource preparation, against 3.3 hours for the comparison group, a saving of 0.8 hours (or 48.6 minutes) a week. The NFER found the quality of Aila-group resources no worse than the comparison group's. The EEF gave the finding a high security rating, according to EdTech Innovation Hub.
Use was light. On average Aila supported 7% of lessons, though 81% of the Aila group tried it at least once. Teachers who used it more saved more time, and the benefit was largest for newer teachers and those less confident in a subject.
What to copy
Run an independent trial with a real comparison group and report the result even when it is lower than your own estimates, as Oak did. Track how often the tool is used, not only the savings, and focus it on the tasks and teachers where it helps most.
All reported figures
| Measure | Figure | Citation |
|---|---|---|
| Weekly time spent preparing lessons and resources by teachers in the Aila group (ten-week trial, autumn term 2025) | around 2.5 hours per week1 | |
| Weekly time spent preparing lessons and resources by teachers in the non-Aila comparison group | 3.3 hours per week1 | |
| Average weekly saving for the Aila group compared with the non-Aila group | 0.8 hours (or 48.6 minutes) per week1 | |
| Time spent by the Aila group as a share of the time spent by the non-Aila group | 76%1 | |
| Share of lessons for which Aila was used on average, with use declining over the ten weeks | 7% of lessons1 | |
| Share of teachers in the Aila group who used it at least once | 81%3 |
Lessons for your project
Test with a control group before you scale. Oak says its own earlier surveys suggested bigger savings than the trial found, so self-reported gains may overstate the effect.
Measure use as well as outcomes. Time was saved even though Aila supported only a small share of lessons, and use fell over the ten weeks.
Design for the work people already do. Teachers mostly wanted to adapt existing material, while Aila was built to plan from scratch, and Oak is now moving its AI into its existing lesson pages.
Target the tool at the people who benefit most. Newer teachers and those less sure of a subject saved the most time.
Caveats
- The trial was commissioned by the EEF and run by the NFER, which describe the results. Oak, the tool's maker, published its own summary. The EEF report pages returned an access block when opened, so the figures were read from the NFER summary page, Oak's blog and a trade press report.
- Both groups could use other AI tools such as ChatGPT or Microsoft Copilot. The trial compares teachers encouraged to use Aila with teachers asked not to use it.
- Teachers' views were mixed: ETIH reports that fewer than one in five said Aila had meaningfully changed their teaching or planning, and many preferred other AI tools. The NFER notes that outputs often needed adapting before use.
- The sources do not name the model used during the trial. An Oak blog post dated 17 December 2024 said Aila then used OpenAI's GPT-4o and that Oak could change models, so the trial model may differ.
- Aila launched in beta in 2024 according to ETIH, so the deployed date is shown as 2024 only. The trial ran in autumn 2025. ETIH is dated 7 October 2026 and the NFER and Oak pages 6 October 2026.
- Oak says Aila has changed since the trial. The results describe the autumn 2025 version. Aila is free to use, and none of the sources give a cost.
Sources
- Lesson planning using AI lesson assistant, Aila - A Teacher Choices Trial
NFER (for the Education Endowment Foundation) · 2026-10-06 · Research paper · nfer.ac.uk
- You're likely already using AI. Here's where we fit in
Oak National Academy · 2026-10-06 · Company blog · thenational.academy
- Oak's Aila saves primary teachers 49 minutes a week on lesson planning, EEF trial finds
EdTech Innovation Hub · 2026-10-07 · News · edtechinnovationhub.com
- Understanding the 'Ai' in Aila
Oak National Academy · 2024-12-17 · Company blog · thenational.academy
Summarized in our own words from the sources above. Spotted an error? See corrections.