[Linkpost] “The best cause will disappoint you: An intro to the optimisers curse” by titotal

This is a link post.

I would like to thank David Thorstadt for looking over this. If you spot a factual error in this article please message me. The code used to generate the graphs in the article is available to view here.

Introduction

Say you are an organiser, tasked with achieving the best result on some metric, such as “trash picked up”, “GDP per capita”, or “lives saved by an effective charity”. There are several possible options of interventions you can take to try and achieve this. How do you choose between them?

The obvious thing to do is look at each intervention in turn and make your best, unbiased estimate of how each intervention will perform on your metric, and pick the one that performs the best:

Image taken from here

Having done this ranking, you declare the top ranking program to be the best intervention and invest in it, expecting that that your top estimate will be the result that you get. This whole procedure is totally normal, and people all around the world, including people in the effective altruist community, do it all the time.

In actuality, this procedure is not correct. The optimisers curse is [...]

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Outline:

(00:26) Introduction

(02:17) The optimisers curse explained simply

(04:42) Introducing a toy model

(08:45) Introducing speculative interventions

(12:15) A simple bayesian correction

(18:47) Obstacles to simple optimizer curse solutions.

(22:08) How Givewell has reacted to the optimiser curse

(25:18) Conclusion

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First published:
February 11th, 2026

Source:
https://forum.effectivealtruism.org/posts/q2TfTirvspCTH2vbZ/the-best-cause-will-disappoint-you-an-intro-to-the

Linkpost URL:
https://open.substack.com/pub/titotal/p/the-best-cause-will-disappoint-you?r=1e0is3&utm_campaign=post&utm_medium=web&showWelcomeOnShare=true

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Narrated by TYPE III AUDIO.

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