Doing your best on a high-stakes English proficiency test like the DET is primarily based on your language skills. But it’s also important to be ready for the test itself, and that means practicing all aspects of taking the test.
Most providers of high-stakes tests offer a practice test for this purpose. Unfortunately, practice tests often contain a fixed set of items, limiting the number of times a test taker can meaningfully engage with them in order to feel ready for the official test.
But we do things a bit differently! The DET uses human-in-the-loop AI to automatically generate test items. “Human-in-the-loop” means that there is human oversight at all stages, including human review of every item for linguistic quality and cultural sensitivity.
And we take this same approach to the practice test! This method generates a large pool of high-quality practice test items, giving test takers unlimited opportunities to familiarize themselves with the test format and task types. Like the certified test, the practice test is adaptive, so test takers receive a new set of items with each repetition. This maximizes test takers' exposure to a variety of items, increasing their familiarity with the test.
The power of Duolingo’s unlimited Practice Test
Can an AI-powered practice test actually help test takers feel more confident and perform better on the DET? Our latest study investigates this very question.
To better understand the impact of AI-powered practice tests, we analyzed data from a survey of over 25,000 test takers. We examined their engagement with the practice test; their confidence, motivation, and anxiety levels; their official test scores; and their likelihood of sharing their results with universities.
Key findings: More practice equals more confidence
Our research revealed four major insights:
- Increased practice leads to greater confidence. Test takers who took more practice tests reported higher confidence levels when taking the official test. They also felt more prepared and motivated compared to those who took fewer or no practice tests.
- Moderate practice is associated with stronger performance. Test takers who took the practice test 2–3 times achieved slightly higher certified test scores on average than those who practiced either more or less. This suggests that moderate engagement with AI-powered practice tests is sufficient for test takers to test their best.
- Anxiety levels remain stable. This finding underscores the stress that high-stakes testing can induce, which is why DET assessment specialists consider the test-taker experience (TTX) when designing the test. Anxiety levels remain stable.
- Confident test takers are more likely to share their scores. Those who felt prepared and motivated were more likely to share their official test results with universities. This indicates that practice tests may not only improve test-taking experiences but also encourage test takers to move forward with their academic goals.
Why this matters
These findings highlight the potential of practice tests made with human-in-the-loop AI to support test takers in a meaningful way. By providing free, unlimited, adaptive practice opportunities, generative AI helps test takers feel more confident and prepared, which can ultimately lead to better outcomes in their academic and professional journeys.
At Duolingo, we strive to make test preparation as effective and accessible as possible. Our practice test is just one example of how we use technology to support learners worldwide. As we continue to research and improve our assessments, we remain dedicated to ensuring that every test taker has the tools they need to succeed.