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This is an evergreen post. It’s linked from the header, and will be updated periodically. If I’ve made mistakes not listed here, let me know and I’ll issue a correction.

Vaccine Acceptance

Post: Was Vaccine Production Actually Delayed?
Summary: I wrote that historical ills, including the Tuskegee study may play a role in diminishing vaccine acceptance. Two links from Marginal Revolution (1, 2) indicate that there is no link.
Severity: Minor. This was an appendix to the post, and not central to the argument. Both links are to article published after my post, but one references this study published in 2007. So it only has a minor impact on my argument, but I am moderately embarrassed.


Post:: Isolated Demands for Rigour in New Optimism
Summary: Noah Smith is currently on part 3 of a 4 part rebuttal. I haven’t taken a good look yet, but will write a response if appropriate once the series is complete.


Post: How Substack Became Milquetoast

Type: Factual errors.
Summary: I wrote that Substack had 44 employees based on their LinkedIn profile. Nadia corrected me, they only had 17 employees at the time.
Severity: This weakens my argument that Substack has failed to use it’s immense resources effectively, but does not defeat the central thesis and is only mentioned in an epilogue to the main article.
Response: The article is corrected, with the original error preserved for posterity. An apology was issued over email.

Type: Punching down.
Summary: When I wrote this article, Substack was widely hyped, and had received little substantial criticism. Since then, they have been the subject of various critiques, some of them quite poor. As a result, I somewhat regret associating with this side of the argument. See for example, the misleading NYT headline The Site Trump Could Run To Next, and Here’s why Substack’s scam worked so well. My critique was focused on Substack as a replacement for eclectic blogs. I neglected to mention that it seems to be a much better replacement for op-ed pieces, and many of my criticisms do not apply in this capacity.

Effective Altruism Slowing Down

Post: Why Hasn’t Effective Altruism Grown Since 2015?
Type: Incomplete analysis.
Summary: Katja Grace wrote a reply, pointing out that I neglected several pieces of evidence pointing at continued growth. She was kind enough to email this to me directly.
Response: I wrote a reply here, agreeing with many of Katja’s points, but defending the bulk of my original piece.

Effective Altruism Shifting Priorities

Post: Responses and Testimonies on EA Growth
Type: Misattribution.
Summary: Scott Alexander wrote this comment, which I attempted to summarize in a follow up post. He then wrote that my summary of his position did not accurately capture his views.
Response: The summary was amended, and a retraction was added as a footnote.

S&P Annualized Returns

Post: The Byrne Hobart Portfolio
Type: Factual error.
Summary: I wrote that the S&P had returned “113.7% annualized since the May 2020 bottom”. The bottom was in March, not in May, giving annualized returns of 76.6%, not 113.7%.
Severity: Minor. The article is about how good Byrne’s portfolio is, and the mistake only strengthens this stance.
Response: This is corrected in the article. The original mistake is preserved and noted.

Forecasting Herd Immunity

Post: Contra StatNews: How Long to Herd Immunity?

Type: Misinterpreting evidence.
Summary: I wrote that antibodies only last 8 months. Alvaro noted that the papers actually indicate antibodies lasting at least 8 months.
Severity: Moderate. This alters projections by 1-2 weeks depending on other parameters. I was careful to list out model assumptions, but had said that antibody duration was among my more confident assumptions. There is an “Speculative armchair epidemiology” warning at the top of the article. This does not affect the central criticism of the original Stat News article. I repeatedly noted that the estimates should not be taken too seriously.
Response: This is noted in the article with a detailed correction.

Type: Mistaken assumptions.
Summary: Despite having previously summarized the survey data on vaccine acceptance, I neglected to realize just how low it would continue to be. I also forecasted 200,000 new confirmed cases per day, but they have since dropped drastically.
Severity: Moderate/Low. I didn’t account for low vaccine acceptance, or the lack of a vaccine for children. I did note that daily confirmed cases was my lowest confidence assumption.
Response: None.

Age of Top YC Founders

Post: Replying to Robert Wiblin on Young Rationalists
Type: Factual error.
Summary: I got a couple ages wrong in the original spreadsheet. Mean/median age at founding was previously listed as 26, but is actually 27. Mean/median age in 2020 was listed as 36 and 35, but are actually both 37. Thanks to Gytis Daujotas for catching these.
Severity: Minor. Ages are off by 1 or 2 years, which slightly weakens my argument.
Response: The post and data has been corrected, with the original mistake noted.