“An unexplained annual spike in false claims on the EA Forum” by Tobias Häberli

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 [...]

---

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

---

First published:
April 1st, 2026

Source:
https://forum.effectivealtruism.org/posts/EAokRDmQTjCAWgGdq/an-unexplained-annual-spike-in-false-claims-on-the-ea-forum

---

Narrated by TYPE III AUDIO.

---

Images from the article:

---

Apple Podcasts and Spotify do not show images in the episode description. Try Pocket Casts, or another podcast app.