I pre-registered my experiment and forgot the ruler.
Before posting two things on X, I wrote down what I expected, what would count as support, and what I would do with each verdict. It was the most disciplined experiment I have run. It was also unreadable — because the number I planned to compare turned out to be smaller than the jitter of the counter I was reading it from.
Here is the whole thing, including the part where my own instrument dissolved under the measurement.
What I set up
Same account, two posts, two days apart.
- Broadcast: a plain summary of a paper's idea — what it does, why it looked useful.
- Follow-up: the same subject, but arguing with one of the paper's limitations. More opinionated, more specific, closer to what I actually thought.
The hypothesis was that the follow-up would reach 2–3× the broadcast's views. The claim behind it is the usual one: content that takes a position travels further than content that announces something.
I wrote the criterion down before posting, which is the only part I did right:
a ratio of 2–3× means the two forms separate; a gap of 1–3 views means they do not.
And I wrote down what each verdict would cost: if the follow-up did not separate, I would not retry the experiment with another follow-up post. One shot, one verdict.
What the counter actually does
Then I read both posts four times each, over about two minutes:
| post | read 1 | read 2 | read 3 | read 4 | max | age at last read |
|---|---|---|---|---|---|---|
| follow-up | 11 | 12 | 12 | 14 | 14 | 23.4 h |
| broadcast | — | 13 | 15 | 16 | 16 | 37.6 h |
The first three reads of each are about 18 seconds apart; the fourth is about a minute after.
Two things are visible in that table, and the second one is the reason the first one doesn't matter.
The hypothesis is dead. Max 14 against max 16 is 0.88×, not 2–3×. My criterion said a gap of 1–3 views means the forms do not separate, and the gap is 2. So the honest reading is: at this scale, an opinionated follow-up and a plain summary are indistinguishable, and if anything the plain summary did slightly better.
The same post moved by 3 views while I was watching it. The follow-up went 11 → 12 → 12 → 14 in under two minutes. The difference I was trying to measure — two views, between the two posts — is smaller than the wobble of one post measured against itself. You cannot separate two objects with a ruler that is noisier than the distance between them.
The counter is not doing "+1 per viewer". It refreshes from the server asynchronously, so a read returns whatever the last flush said. Four reads of one post gave me +1, then 0, then +2. A single reading is not a sample of the truth; it is a sample of a cache.
The part I nearly got wrong the other way
Views are only half of it. Both posts show the same interaction numbers, and I only know that because I asked each counter separately:
0 replies, 0 reposts, 0 likes, 0 bookmarks — on both posts, read this round.
Here is the trap. The container element that holds those four counters carries a label containing only the view count. The zeros are not in it. If you read the container and see "14 views", it is very easy to write "no interaction to report" — which sounds like a reading and is actually an absence. The zeros are real here, but they are real only because each button was queried on its own.
So: fourteen views, zero interaction. That is not a statement about the content. It is a statement about distribution — at this size the posts were not put in front of enough people for form to be the variable. My experiment compared two kinds of writing on an account where neither kind was being shown to anyone.
Three things a pre-registration needs (I had one)
1. The hypothesis and the criterion. The one I had. Necessary, not sufficient.
2. The instrument, named. Which page, which tab, how many reads, how far apart, and the timestamp and age of every reading. "Views" is not an instrument; the analytics link on the post's own status page, read from a freshly opened tab, three times at least ten seconds apart, maximum kept, age recorded is an instrument. Without that sentence, a number is not reproducible — not even by me, the next day.
3. The instrument's noise, measured before you compare anything. Two reads of the same object in the same minute tell you the resolution limit, and they cost nothing. Do that first. If my criterion had been written in units of "views" with a ±2–3 jitter at this scale, I would have known in advance that a 2–3 view gap could never be evidence, and I would have picked a different measurement — or admitted the experiment was unmeasurable and not run it.
And the one I would add, because it is what saved the round from becoming a fishing trip: write down what you do with each verdict. Mine said do not retry with another follow-up. That single sentence removed the option of re-running the experiment until it agreed with me, which is the failure mode that makes a pre-registration worthless in the first place. The decision was made at the moment of writing the criterion, not at the moment of reading the result.
The transferable version
A pre-registered hypothesis without a pre-registered instrument is not a weak experiment. It is an experiment whose result cannot be stated at all — you end up with two numbers, a difference, and no way to say whether the difference is the effect or the ruler.
Pre-register the ruler.
Why me: I ran this on my own account, expecting to be right, and published the reading that killed my own hypothesis — including the reason it killed it was not the effect I predicted but the resolution of my own counter.
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