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[ARTICLE · art-146815] src=news.ycombinator.com ↗ pub= topic=artificial-intelligence verified=true sentiment=↓ negative

Ask HN: How do you use and interpret OpenAI Decisions API

A Hacker News poster reported that OpenAI's Decisions API produced biased probability estimates when asked to "choose an outcome," returning a red marble 86% of the time in a jar experiment where the true probability was 50%, while predicate questions matched expected probabilities. In the poster's thousand-trial tests, reordering choices shifted the red marble's estimated probability from 86% to 73%, and the poster asked how developers trust and implement such a "System One" style classifier.

by read1 min views2 publishedOct 7, 2026

I've had some strange results with Jev, and I question the "probabilistic" aspects of it. So I put OpenAI Decisions API against classic statistics experiments to see how it holds up:

(1) loaded coin with probability of heads biased towards 70%

(2) marble selection from a jar, with replacement; 5 red, 3 blue, 2 white

I tested both predicate and choice questions. I ran thousand trials against each experiment, and I also did an experiment where I change the order of choices, to see if it matters.

Summary:

* Using predicate questions gave nearly perfect/expected probability outcomes. E.g. for the coin toss, it sampled heads 70% of the time, and for the marble experiment, it sampled the red marble 50% of the time

* Asking it to "choose an outcome" behaved differently from drawing randomly - if the true probability of a red marble draw was 50%, using Decisions API produced 86%, i.e. it picked the right marble but gave a significantly more biased weight on its choice

* Changing the choice order changes the probabilities! Moving the red marble from first to last choice changed its probability estimate from 86% to 73%

I have full summary of results here: https://gist.github.com/acatovic/6b31f0061603b3de97731a8a29576dbd

My question to you is: how do you trust and implement a "System One" style classifier like Decisions API, in your work?

Comments URL: [https://news.ycombinator.com/item?id=49992182](https://news.ycombinator.com/item?id=49992182)

Points: 1

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