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 April 1 is only 1/365 of the year, so the overall impact should be small. I don't think that survives scrutiny.


First, because the Forum has a global user base, the relevant window is not 24 hours. Once April 1 begins in New Zealand, there are still many hours before it ends in Hawaii. Depending on how one defines exposure, the annual high-risk period is closer to 45 hours.


Second, posting volume itself increases during this window. Total post count is roughly 3.5x the daily average. So this is not just a higher rate of false claims but also a higher number of them.


Putting those together, April 1 appears to account for something like 8–12% of all false claims on the Forum annually, despite being only a single calendar date.


4. The false posts are high effort

Perhaps most concerningly, the April 1 posts are not low-effort. Many are long, well-formatted, and written in a tone of serious analytical posts. Some include fake citations, fabricated statistics, and made up organisations. At least one included an appendix.

Possible explanations

At this point I do not have a theory. We might never really know.


Why this matters

The EA community places a strong emphasis on truth-seeking, calibration, and careful reasoning. With that in mind, it seems highly concerning that there is one predictable period each year during which a large fraction of content is false.


If an airline knowingly allowed 60% of its planes to crash for one day every year, we would not regard that as reassuring just because it was predictable. We would ask why it was happening and how to stop it. The posts on April 1 are crashing our epistemic infrastructure in much the same way.


Using conservative assumptions, April 1 posts appear to consume roughly 200–270 author-hours and 2,600 reader-hours per year. At $50/hour, that implies a direct productivity cost of roughly $140,000–$180,000 annually, excluding second-order effects like moderation burden, confusion, reputational damage, and erosion of trust.

In other words, each year the April 1 spike burns the equivalent of one statistical EA researcher every year. If this happened on any other day, we would treat it as an emergency and act to make sure no statistical EA researcher ever suffered like this again.


Proposed interventions

I see three plausible responses:

1. Freeze or discount karma on posts published during this period until they have been independently reviewed by at least two Forum users who were not themselves posting on April 1.
2. Staff a volunteer rapid-response team for April 1 fact-checking, potentially funded as a full EA org if the problem proves harder than expected.
3. If 1. and 2. fail, we might need to disable new posts during the relevant period each year. We could show a holding page explaining that the Forum is undergoing scheduled epistemic maintenance.
4. For one day each year, Forum users demonstrate an unexpected ability to produce  highly engaging content. Currently this skill is deployed almost entirely toward falsehood. If the underlying mechanism was understood, we might be able to redirect it towards highly engaging writing on true claims.

[Edit: Someone pointed out that our classifier flagged this very post as well. We're looking into this and will update when we understand why.]