Summary: For first-time authors who are also long time members of the EA movement, they have used the title of 'co-founder of effective altruism', or some variation thereof (e.g. "co-founder of the effective altruism movement). However, it does not appear being among the cohort of individuals who formed the initial core of the EA community by joining between the critical, initial years of 2009 and 2011 is highly predictive of how impacftful an individual effective altruist might be judged to be. Neither has anyone in EA ever assessed if EA as an idea or movement has gained enough public exposure for the distinction 'co-founder of EA' to have an impact on the public perceives a given individual co-founder. So, it appears to me that the distinction between who qualifies as a 'co-founder' of EA has thus far been of little to no consequence.

There are a few people who have been cited as 'co-founders of effective altruism', usually authors of books on EA topics, perhaps as part of an effort to sell books, or as pressured by the publisher.

• I remember on some editions of Doing Good Better, William MacAskill is cited as a 'co-founder of effective altruism.'
• Jacy Reese is cited as well on his recent book The End of Animal Farming as a co-founder of EA as well.
• Peter Singer has written a couple books about EA now, and I don't know if he is cited in or on any of them as a co-founder of effective altruism, but he would definitely qualify.

I've seen people ask questions about this on social media, since 'co-founder of effective altruism' is a vague, and potentially contentious, title. The qualification I've seen given is each of these individuals are those who have been part of the EA movement since the beginning, even before the nascent community was called 'effective altruism', and that they helped shape the principles and goals of the EA movement that community would become.

Historically, the following organizations were the earliest to be associated with what would become EA:

• Givewell, launched in 2007
• LessWrong, launched in 2009
• Giving What We Can, launched in 2009
• 80,000 Hours, launched in 2011

It's with multiple organizations, and the communities that built up around them, connecting online that first developed the community that would become 'effective altruism.' This started in 2009. It was with the launch of 80,000 Hours in 2011 that community began to grow, and the label 'effective altruism' began to stick. However, EA's growth rate dramatically accelerated in 2013 with Peter Singer's TED talk on effective altruism, which received over 1 million views.

So, to be a "co-founder of EA" would be to someone who joined as a central member of the community sometime between 2009 and 2013, most likely between 2009 and 2011. Depending on what other factors one would apply to qualify or disqualify a "co-founder" of EA, this would put the number of co-founders between a couple dozen to a few hundred people. To do more than that gets into who is some kind of primary co-founder of EA, i.e., who deserves the most credit. It's not my experience the EA community considers that a debate worth having. With the number of people who could qualify as 'co-founders' being as many as it is, qualitatively, it might make the title feel less special. However, it's not clear to me being a 'co-founder of effective altruism' is a distinction that predicts a lot about how impactful a given member of the EA movement is.

As far as I can tell, most people who would qualify as co-founders of EA I've talked to would say EA has become much better, and succeeded much more, in the years since its beginnings. Changing to become more effective is a principle of EA, and it was necessary for EA to change become more effective over the years. A necessary part of changing to become more effective was growing as a movement, and onboarding new members who made unique and valuable contributions necessary to EA's success. Ergo, there isn't a common belief in EA that the movement's founders are a special class in the community whose credit for launching the movement extends beyond gratitude from people who joined EA since it started. This makes sense, as EA ostensibly cares about doing what's effective, not who was part of the community first.

It's also not clear citing a founding effective altruist as a "co-founder" of EA when they author a book does much for the book's sales, or the credibility of EA. I don't know the rationale for citing Jacy Reese and William MacAskill as co-founders of EA for their books, or if that was a publisher's idea. Perhaps it was thought that the EA movement had received enough credibility and attention that associating Jacy or Will with EA would boost their credibility. However, while at least a couple million people may have at least heard of EA, through Peter Singer's TED talk and other media, most of that hasn't translated to lasting growth for EA. The biggest count for potential membership of EA is the 'Effective Altruism' Facebook group, which currently stands 16,482 members. So, at most, EA sits at between 10k and 20k members, at least two orders of magnitude lower than the number of people who have presumably been exposed to EA as an idea or movement.

It's not clear the initial impressions of EA the 99%+ of people who didn't follow through in eventually joining the EA community had much of a lasting impact on them. So, it might be incorrect to assume associating a first-time author with effective altruism will make people think more highly of the author, simply because not enough people may have yet heard of EA for such an effect to materialize. It seems just as plausible associating EA with a first-time author will make readers think more highly of EA, since they'll then have heard of EA as a movement important enough to be associated with a published author. It's funny to say, but EA could still have reached so few people that that could be the reality.

Of course, for a variety of reasons EA won't appeal to a lot of people, or perhaps even most people. To my knowledge, there has been no public conclusion yet on what proportion of people EA ultimately could or should be aiming to reach. The top source for exposure to EA is apparently Peter Singer's TED talk, which currently has ~1.7 million views on TED.com. Through other media sources, and word of mouth, it seems like EA would have been exposed to at most several hundred thousand people. I doubt more than 3 million people have heard of EA.

EA has had its greatest exposure throughout Europe, and English-speaking developed countries. With the population of the United States at ~320 million; ~740 million in Europe; and ~67 million across Canada, Australia, and New Zealand, there is a population of ~1.127 billion across the countries EA has gained a relatively wide exposure in. If we were to assume only 1% would want to potentially become part of EA in the first place, that is a population of ~11 million people who might potentially join EA if they were exposed to the idea/movement. Of course, even fewer people than that might join the movement in practice. Still, since there is only evidence for only a couple million people having been exposed to EA as an idea, 1% of the combined population of the countries EA has created a lasting presence in would leave almost 10 million people who we would want to expose to EA to see if they might join.

Note that this hypothetical model doesn't account for:

• How EA might be exposed in the future to more people in the countries it's already established a presence in.
• How EA will expand to countries around the world further from the countries it originated in (mainly the UK, the US, and Germany).
• That the 1% of the population who 'might potentially join EA if exposed to it' is just an assumption, and not a real number. Whether a constructed metric like that is the most sensible measure to go with; how difficult it would be a measure; and what its amount would be are all crucial factors which have not been researched or established in EA.

Still, the number of people who have heard of EA, and who also have a good impression of it, seems small enough it seems very unlikely random people who come across books written by authors from the EA community will have preexisting good impression of EA. The same goes for if a random person were to hear someone was a 'co-founder of effective altruism' in conversation. Part of doing what's effective is doing what works, which means following up on the consequences of our actions.

Overall, the idea of branding someone as a 'co-founder' of EA for the purpose of boosting their reputation by associating them with EA is based on the assumption a sufficient proportion of the population has a preexisting, good impression of EA for that to make a difference. However, there is not nearly enough evidence to back that assumption. Thus, there isn't much reason to expect someone bearing the title 'co-founder of effective altruism', as an author or another kind of public figure, has much effect on how the public perceives them, positive or negative.

Regardless of who qualifies as a 'co-founder' of EA, it doesn't appear the precise attribution of this credential is super critical for the achievement of the EA community's goals, and nobody has assessed if it has an effect on the public perception of the co-founders. Of course, credit is due to whoever would qualify as a co-founder of EA under whatever criterion, and this doesn't mean the rest of the EA community should not be grateful to the founders of the movement. There is just evidence one way or another if the title of co-founder of EA has an impact on the public perception of either the individual in question, or EA as a movement.

One impact of this analysis is that first-time authors, or other aspiring public figures or public intellectuals, who are also part of the EA community, might do better by primarily building up a positive public reputation for themselves, and a positive relationship with their audience, instead of primarily emphasizing their association with EA. There isn't evidence associating with EA will have negative consequences either. It's just the case that the reputational effect could be reversed than has previously been anticipated, and that an EA-aligned author or public figure who establishes a public reputation will cause many more people to be exposed to EA ideas, or join the EA community.