EDIT: the recommendations have now changed. Vote for Joe Biden.
Voting is a pretty impactful activity in expectation, so I and some other contributors have spent a good deal of time on the Candidate Scoring System for Democratic presidential candidates. The latest version of the report is available here: http://bit.ly/ea-css
As primaries for the first states begin within a week, here are the latest recommendations. They depend upon your state of residence. For voters in the first three states - Iowa, New Hampshire, and Nevada - the recommendation is to vote for Pete Buttigieg (unless he fails in Iowa and is no longer a serious candidate). For voters in subsequent states - South Carolina, and all the Super Tuesday states including California - the recommendation is to vote for Mike Bloomberg. The reason for the difference is that both are good and it seems more tractable to help candidates in their strong states which are key to their strategy.
The conclusions are, necessarily, controversial. But I went to great lengths to score as rigorously as possible in this context before arriving at these latest conclusions. Counterarguments/counterevidence against all manner of objections are present in the report. But, this being the EA forum, I'd like to specifically highlight and address upfront the main reasons that EAs have disagreed with this report.
1) "Joe Biden is best because he is electable." While he is the most electable according to both electoral theory and current polls matching candidates against Trump, lesser-known candidates will improve in such polls if they get nominated and have more chances to communicate with voters. And some of the people answering in favor of Biden may be judging on the basis of 2008-2016 memories, and may change their mind if they become more aware of Biden's apparent cognitive decline. And generally speaking, these electability judgments are not robust. Therefore, there is not a good case for the idea that Joe Biden is so much more electable that he ought to be preferred over significantly more meritorious candidates.
2) "Bernie Sanders is best because he won't fight wars which cause massive suffering." Well as best as I can tell, the naïve populist-pacifist idea that we should cut our military spending and exit Iraq/Afghanistan/Africa would make things worse around the world. (Do you really think the war in Afghanistan will end just because the US pulls out?) It is admirable that Bernie opposed the regime change wars of the Bush Doctrine, but in other typical contexts of US foreign policy, retrenchment is harmful overall (unless we need to save American blood and treasure). This seems to be a near-consensus among foreign policy experts. Bernie was right about Iraq in 2003, but wrong about it in 2004, 2005, 2006, etc. And candidates like Mike and Pete are not dumb or hawkish enough to do something similar to the invasion of Iraq, we've all learned from it. In my recent foreign policy posts on this forum - my response to progressive foreign policy, and my own recommendations - I did not receive counterarguments to my rejection of Sanders' (and Warren's) brand of non-interventionism. Nor have I seen any other Effective Altruists analyze these issues with rigor; my fellow EAs seem to largely be repeating common-sense appealing opinions that they picked up from ordinary political socialization before or outside of their EA involvement. So I am increasingly confident that my object-level opinions are simply correct and that the mere opinions of pacifist EAs and EA-adjacent people do not carry significant weight. And of course, many EAs do not share these pacifist opinions.
Note: I still regard Bernie Sanders as one of the better candidates in foreign policy. I just reject the idea that he's much better than the others, which is the judgment that would be required if you wanted to write off his flaws.
3) "Bernie Sanders is best because he will give us the strongest social welfare and redistribution." But it's not clear whether moderate-Democrat ideas for things like housing, healthcare, education, etc are systematically better than progressive-Democrat ideas on the same topics. Criticism of progressive-left domestic agendas has come from a variety of reliable sources which have done a good job of withstanding leftist rebuttals. There are both pros and cons to Bernie's domestic agenda, not much different from other candidates. Also, much of Bernie's agenda will fail anyway given the likely obstacles in the Senate.
4) "Andrew Yang is best because he recognizes AI risk." But between the fact that it's very hard to say what a president should do to manage AI risk, and the fact that AI risk is not objectively a greater threat than things like nuclear war and climate change by my calculation (it's just more neglected, and that doesn't matter so much from the President's perspective), Yang's AI comments do not change much. Also, he has almost no chance of winning.
5) "The underlying weights are too subjective and arbitrary." I have tried to keep them close to the center of informed EA opinion, unless I have good arguments or evidence to the contrary. Feel free to play around with the Excel model and apply your own. I find that most plausible variations in weights don't change the conclusions. The main sensitivity to intra-EA disagreement over priorities is that a very short-term focused view should focus on Mike and ignore Pete. Biden can become very good or very bad under different assumptions; even if your weights put Biden ahead, I think you should still vote for Mike due to the Optimizer's Curse.
Note: I'm receptive to EA or EA-adjacent media, journalists, podcasts, etc who want to spread knowledge of this.
Feedback welcome, and please get out there and vote.
Also, if you want more frequent updates, follow me on Twitter: https://twitter.com/KyleBogosian