TL;DR
Primary teachers who used Aila, the AI lesson assistant from Oak National Academy, spent 24% less time preparing lessons, with no drop in the quality of what they produced, according to a randomised trial whose results were published on Tuesday 6 October. But the tool was used sparingly, use fell away over ten weeks, and teachers’ opinions of it were mixed.
What the trial measured
The Education Endowment Foundation (EEF) commissioned the study, and NFER carried it out. It covered 464 teachers of Years 3 to 6 across 108 schools during the autumn term of 2025. Teachers were randomly assigned either to plan with Aila or to avoid it, though both groups were free to use other AI tools.
Teachers with Aila spent around two and a half hours a week on lesson and resource preparation, against three hours 19 minutes for the comparison group, a saving of about 49 minutes. Independent assessors judged the Aila group’s resources to be no worse. The EEF gives the finding a high security rating.
Low use, mixed views
The time saving came despite light use. In the Aila group, 81% opened the tool at least once, but in a typical week it supported only about 7% of lessons. Those who used it more saved more.
The benefit was biggest for teachers early in their careers, those less sure of their subject or teaching knowledge, and those comfortable with technology. Under a fifth said it had meaningfully changed how they taught or planned, and many preferred other AI tools. The researchers point to a mismatch: Aila is built to plan lessons from scratch, while teachers often adapt material they already have, and its output frequently needed editing before classroom use.
Looking forward
The result sits alongside an earlier EEF trial in which Key Stage 3 science teachers using ChatGPT cut preparation time by 31%. The settings differ, secondary science against primary teaching across subjects, so the two numbers are not a direct contest. In our view, though, a general chatbot producing the larger saving while a purpose-built, curriculum-aligned tool struggled to hold teachers’ attention is telling. The lesson for schools is that a free tool does not guarantee use, and the EEF itself suggests targeting AI planning tools at newer or less confident staff. Pupils’ side of the question is getting attention too: a Scottish school has just appointed a principal teacher of AI literacy.