New "Slop Index" Benchmark Measures How Much AI Writing Sounds Like AI
The tells everyone recognizes
Anyone who reads a lot of AI-written text has spotted the pattern: a throat-clearing opening line, a tidy "rule of three" list, or the phrase "it's not just X, it's Y." These habits have earned a nickname online — "AI slop" — shorthand for writing that feels mass-produced rather than genuinely composed.
Eighteen models, one open-source scorecard
According to a post shared on Reddit, one developer decided to measure this tendency statistically rather than just complain about it. The result is an open-source benchmark called the Slop Index, published at theslopindex.com. The method starts with a baseline: a corpus of real human writing gathered across categories such as email, social posts, chat messages, and essays. Text generated by 18 different AI models is then compared against that human baseline to see how far each model's phrasing drifts from natural human writing.
Why it matters
As AI-generated text becomes more common online, spotting which models write in a distinctly "AI" voice — and which come closer to natural human prose — has become a practical concern for writers and readers alike. The benchmark is an independent, self-published project, and its rankings have not been independently verified, but it offers one of the first attempts to quantify "AI slop" rather than simply describe it.
A New Tool Ranks How "AI-Sounding" AI Writing Is
AI writing often has a certain feel to it. Now there's a way to measure that.
💡 The gist
- AI writing often repeats the same phrases and patterns
- Someone built a tool called the Slop Index to measure this
- It compares 18 AI models to see which sound most human
When AI writes, it often starts sentences the same way or wraps things into "three neat points." People call this "AI slop." It happens because AI models learn from huge amounts of text and pick up on patterns that show up again and again, so they tend to reuse those same patterns.
To test this, a developer built a tool. First, they collected real writing from humans — emails, social posts, chats, and essays — to use as a baseline. Then they compared that to writing from 18 different AI models, scoring how much each one leaned on typical "AI" phrases. The tool is free for anyone to use, and it gives people a way to see which AI models write in a way that feels closer to how humans actually talk.
A Tool That Checks Robot Writing Tricks
Robots that write words have some funny habits.
Robots can write stories. But they use the same words a lot. Like "first, this is important." People call that "AI slop."
Someone made a checking tool. It looks at real people's writing. Then it looks at robot writing. It compares eighteen robots. It shows which robot sounds most like a person.