From 2020 to 2024 - A look at the evolution of the DET - guide for institutions

Aug 29, 2026

Uploaded by Eden

The document explains how the Duolingo English Test (DET) evolved from 2020 through 2024 to support universities and international applicants amid pandemic disruptions. It reviews updates to item types, test design, delivery, and scoring models, including refreshed concordance and expanded item banks supported by generative AI. It also details strengthened security and proctoring, improved ID verification, and expanded access initiatives such as free tests and readiness resources.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages4

Reading Time10 min

AccessFree to download

About the Duolingo English Test

The Evolution of the DET from 2020 to 2024

Test design, delivery & scoring

Security & proctoring

Improving the test taker experience and promoting test access

Item development

Reading

Writing

From 2020 to 2024 A look at the evolution of the DET As test centers around the world closed during the pandemic, universities embraced the Duolingo English Test (DET) to keep the doors open for international students. Institutions who turned to the DET during the pandemic may be unaware of the many improvements we’ve implemented in the years that followed. In the spirit of using the latest technologies in assessment, Duolingo annually updates the DET, introducing new features to better serve test takers and score users. When making these updates, we continually monitor the agreement rate between older and newer versions of the test, to ensure score comparability. This document serves as a guide for institutions looking to understand the DET’s evolution since 2020. About the Duolingo English Test The Duolingo English Test (DET) launched in 2016 as a computer-adaptive, high stakes assessment of English language proficiency for use in English-medium settings, including university study. For maximum accessibility, the DET is delivered online, is available 24/7, and does not require testing centers or appointments. The test uses item types that accurately assess English language proficiency while maintaining feasibility to develop, administer, and score at scale. As of 2024, the DET is accepted as proof of English proficiency by over 5,000 programs andinstitutions around the world. © 2024 Duolingo, Inc. All rights Reserved 1 From 2020 to 2024: A look at the evolution of the DET The Evolution of the DET from 2020 to 2024 Since 2020, the DET has launched several novel item types that extend the measurement of the Academic English construct through authentic, integrated tasks. In addition, we have refined our scoring algorithms and security features, and updated test score concordance with major high-stakes language assessments. We’ve also made advances to our security processes and infrastructure as well as extended our services for test takers. Collectively, the developments to the DET have improved construct coverage in all skill areas, increased score reliability, as well as correlations with scores on other English proficiency tests, all while maintaining the flexible and efficient testing experience that is a cornerstone of the DET’s access mission. A summary of developments includes: Test design, delivery & scoring • Introduced new item types (see below) • Revised concordance in Summer 2022 (also see our article in Language Testing) • Refined the scoring models for speaking and writing • Refreshed and increased our item bank using generative AI ( LaFlair et al., 2023) • Developed a theoretical ecosystem for digital-first assessments that includes testtaker experience as a validity argument ( Burstein et al., 2022) • Audited our test fairness processes and launched a bespoke quality monitoring platform ( Belzak et al., 2023; Liao et al., 2022) • Introducing new Speaking, Writing, Reading, and Listening subscores in July 2024 Security & proctoring • Enhanced foundational security (malicious software/hardware detection, improved plagiarism detection) • Extended imposters/helper detections, novel approaches to coordinated cheating efforts • Implemented state-of-the-art ID verification system Improving the test taker experience and promoting test access • Expanded DET’s Access Program, distributing over 48,000 free tests in 2023 alone • Launched the We Rise Together awards recognising individuals in the higher ed sector who contribute to initiatives that lower barriers to education • Released new test readiness resources, including an updated mobile practice test © 2024 Duolingo, Inc. All rights Reserved 2 From 2020 to 2024: A look at the evolution of the DET Item development SKILL DET TEST ITEMS | READING | DET 2020
C-test
• Complete a text by completing the “damaged” words in a paragraph
• A measure of test-takers’ reading and spelling ability; highly

FAQs

Why did universities increasingly use the Duolingo English Test during the pandemic?

As testing centers closed worldwide, universities adopted the DET to keep access open for international students. The DET is delivered online and available 24/7 without the need for test centers or appointments.

What major changes were introduced to the DET’s test design and scoring since 2020?

The DET added new item types, refined scoring models for speaking and writing, and updated test score concordance (including a Summer 2022 revision). It also refreshed and expanded the item bank using generative AI.

How did DET strengthen security and proctoring from 2020 to 2024?

Security enhancements included malicious software/hardware detection and improved plagiarism detection, along with expanded detection of imposters and coordinated cheating attempts. A state-of-the-art ID verification system was also implemented.

Aug 29, 2026

Uploaded by Eden