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Jev Headline Bench

Upworthy's randomized headline A/B tests, filtered to variants that shared an image: Jev picks the click winner 64.5% of the time on a held-out confirmatory split, and 74.7% when the real gap was decisive.

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0
Language
Go
License
MIT
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Community
Author
Gaurav-Gosain
Last verified
Oct 2026

Can Jev pick the winner of a real headline A/B test? 64.5% across 10,984 Upworthy randomized experiments, 74.7% when the difference was decisive.

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Updated Sep 2026

Repo stats from the GitHub API, cached Oct 2026.

About this project

Can Jev pick the winner of a real headline A/B test? Built on jev-go. Yes. 64.5% on 10,984 randomized experiments, rising to 74.7% when the two headlines genuinely performed differently. The label here is not anyone's opinion about good writing. Upworthy ran these tests on its own readers: two headlines for the same article, the same image, a randomly split audience, clicks counted. The archive is 32,487 of them. Jev sees the two headlines and nothing else. No article, no image, no date, no click counts.

Quoted from the project's README. Read the full README.

Highlights

  • Confirmatory split: 10,984 pairs at 64.5%, replicating the exploratory split within 0.6 points after every design choice was fixed.
  • Where both headlines performed the same, accuracy sits at 53.1%, and it climbs monotonically to 74.7% as the true gap widens.
  • Jev favours whichever headline is second, so every pair is scored in both orders and averaged, and a test proves a slot-B-only model lands on chance.
  • Confidence is usable: 51.7% right when barely leaning, 78.5% right when it reports 0.80 or above.

Watch out

One publisher, one audience and one era of internet writing: the README is explicit that the question-mark result is about these readers seeing these headlines, not a law of language. Pairs are the best and worst variant inside each test, chosen to maximise the real difference, which makes the task easier than choosing between two arbitrary headlines and means the z statistic on a selected pair overstates its own significance — z is used only to sort pairs into strata and no p-value from it is quoted. Accuracy is measured against which headline actually got more clicks, so a pair where both were equally good is unpredictable by construction, which is why the placebo row is reported rather than hidden inside the average. Single model version, single run. Copy reviewed against the repository README on 2026-10-04, not from running it.

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