Epistemic status: Very high confidence in the statistical findings. Genuinely confused about the cause. For reasons that will become obvious, I wanted to publish this post on March 31, but unfortunately I could only get it done today.
I've been building a classifier to flag potentially misleading content on the EA Forum as part of a side project on epistemics infrastructure. While validating the model, I noticed something I initially assumed was a bug. This is an interim report on that.
Summary: Every year, on April 1, the rate of posts containing verifiably untrue claims spikes by roughly 2,200% relative to the annual daily average (p < 0.0001, 8 years of Forum data).
1. The effect is enormous
On a typical day, approximately 2 to 4% of Forum posts contain claims that are verifiably false. On April 1, this rises to 57–73%, depending on the year. For context, this is an implausibly large effect by normal social-science standards. I have genuinely never seen anything like it.
2. It repeats every year
This is not a one-off event. The pattern recurs in every year of the dataset.
3. "It's only one day" is misleading
A natural reaction is that [...]
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Outline:
(01:00) 1. The effect is enormous
(01:38) 2. It repeats every year
(01:57) 3. Its only one day is misleading
(02:57) 4. The false posts are high effort
(03:21) Possible explanations
(03:30) Why this matters
(04:48) Proposed interventions
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First published:
April 1st, 2026
Source:
https://forum.effectivealtruism.org/posts/EAokRDmQTjCAWgGdq/an-unexplained-annual-spike-in-false-claims-on-the-ea-forum
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Narrated by TYPE III AUDIO.
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