METHODOLOGY
How we measure.
1. Pre & post assessment
Every learner is asked the same 8-prompt speaking diagnostic on day 0 and day 30. The same Cambridge-aligned rubric grades both — by the same model, same temperature, same examiner persona.
2. Human cross-check
1% of all graded sessions are reviewed by Cambridge ESOL-trained linguists every week. AI band estimates within ±0.25 of the human band 93% of the time.
3. Independent audit
Quarterly numbers are signed off by an external L&D auditor and published unredacted on this page. No survivor bias — we include every learner who completed both assessments, even the ones who got worse.
THE GUARANTEE
What happens if it doesn't work.
If your AI-graded speaking band score hasn't gone up by at least 0.5 after 30 days of daily practice (3+ sessions, 5+ days a week), email refund@britwise.info and we refund 100% of the subscription. No hoops. No surveys. No 'are you sure'.