https://slatestarcodex.com/2020/01/13/2019-adversarial-collaboration-winners/

Thanks to everyone who participated and/or voted in the 2019 Adversarial Collaboration Contest. And the winner is…

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Adrian Liberman and Calvin Reese, for Does Calorie Restriction Slow Aging?.

An extraordinarily close second place (26.9% vs. 26.2% of votes) goes to David G and Froolow, for Is Eating Meat A Net Harm?.

Both of these did great research and were written up well. I especially like them as winners because they have such different strengths.

The calorie restriction collaboration was carefully focused on a factual question. I think this is a promising model for adversarial collaborations, and that others failed the further they deviated from this. For example, the circumcision collaboration did a good job assessing the quantifiable benefits and harms of the practice, but it turned out that most people who disagreed about it weren't disagreeing because they assessed quantifiable benefits and harms differently. The abortion collaboration ended up in a similar place. By focusing on a topic where there really was debate about what the research showed, and by hitting the lit review portion out of the park, Adrian and Calvin helped deconfuse a lot of previously confused people.