This post was written for Convergence Analysis, though the opinions expressed are my own. Cross-posted from the Effective Altruism Forum.

This post:

Provides a spreadsheet you can use for making your own estimates of existential risks (or of similarly “extreme” outcomes)
Announces a database of estimates of existential risk (or similarly extreme outcomes), which I hope can be collaboratively expanded and updated
Discusses why I think this database may be valuable
Discusses some pros and cons of using or making such estimates

Key links relevant to existential risk estimates

Here’s a spreadsheet listing some key existential-risk-related things people have estimated, without estimates in it.
- The link makes a copy of the spreadsheet so that you can add your own estimates to it.
- I mention this first so that you have the option of providing somewhat independent estimates, before looking at (more?) estimates from others.
- Some discussion of good techniques for forecasting, which may or may not apply to such long-range and extreme-outcome forecasts, can be found here, here, here, here, and here.
Here’s a database of all estimates of existential risks, or similarly extreme outcomes (e.g., reduction in the expected value of the long-term future), which I’m aware of. I intend to add to it over time, and hope readers suggest additions as well.
The appendix of this article by Beard et al. is where I got many of the estimates from, and it provides more detail on the context and methodologies of those estimates than I do in the database.
Beard et al. also critically discuss the various methodologies by which existential-risk-relevant estimates have been or could be derived.
In this post, I discuss some pros and cons of using or stating explicit probabilities in general.

Why this database may be valuable

I’d bet that the majority of people reading this sentence have, at some point, seen one or more estimates of extinction risk by the year 2100, from one particular source.^[1] These estimates may in fact have played a role in major decisions of yours; I believe they played a role in my own career transition. That source is an informal survey of global catastrophic risk researchers, from 2008.

As Millett and Snyder-Beattie note:

The disadvantage [of that survey] is that the estimates were likely highly subjective and unreliable, especially as the survey did not a

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