Enlarge (credit: Getty Images )

Last week, OpenAI published tips for educators in a promotional blog post that shows how some teachers are using ChatGPT as an educational aid, along with suggested prompts to get started. In a related FAQ , they also officially admit what we already know: AI writing detectors don't work, despite frequently being used to punish students with false positives.

In a section of the FAQ titled "Do AI detectors work?", OpenAI writes , "In short, no. While some (including OpenAI) have released tools that purport to detect AI-generated content, none of these have proven to reliably distinguish between AI-generated and human-generated content."

In July, we covered in depth why AI writing detectors such as GPTZero don't work, with experts calling them "mostly snake oil." These detectors often yield false positives due to relying on unproven detection metrics. Ultimately, there is nothing special about AI-written text that always distinguishes it from human-written, and detectors can be defeated by rephrasing. That same month, OpenAI discontinued its AI Classifier, which was an experimental tool designed to detect AI-written text. It had an abysmal 26 percent accuracy rate.

Enlarge / An AI-generated image of a slot machine in a desert. (credit: Midjourney)

On Thursday, OpenAI quietly pulled its AI Classifier, an experimental tool designed to detect AI-written text. The decommissioning, first noticed by Decrypt, occurred with no major fanfare and was announced through a small note added to OpenAI's official AI Classifier webpage :

As of July 20, 2023, the AI classifier is no longer available due to its low rate of accuracy. We are working to incorporate feedback and are currently researching more effective provenance techniques for text, and have made a commitment to develop and deploy mechanisms that enable users to understand if audio or visual content is AI-generated.

Released on January 31 amid clamor from educators about students potentially using ChatGPT to write essays and schoolwork, OpenAI's AI Classifier always felt like a performative Band-Aid on a deep wound. From the beginning, OpenAI admitted that its AI Classifier was not "fully reliable," correctly identifying only 26 percent of AI-written text as "likely AI-written" and incorrectly labeling human-written works 9 percent of the time.

As we've pointed out on Ars, AI writing detectors such as OpenAI's AI Classifier, Turnitin, and GPTZero simply don't work with enough accuracy to rely on them for trustworthy results. The methodology behind how they work is speculative and unproven, and the tools are currently routinely used to falsely accuse students of cheating.