This seems like it could be true for some of the figures, but not all. Iād strongly expect ānumber of active EA groupsā to correlate with ānumber of total people engaged in EAā. The existence of so many groups may come from people who joined in 2015 and started groups later, but many group leaders are university students, so that canāt be the whole story.
In this case, do you think itās likely that there are about as many group members as before, spread across more groups? Or maybe there are more group members, but the same number of total people engaged in EA, with a higher % of people in groups than before?
I think this applies to growth in local groups particularly well. As I argued in this comment above, local groups seem like a particularly laggy metric due to people usually starting local groups after at least a couple of years in EA. While Iāve no doubt that many of the groups that have been founded by people who joined since 2015*, I suspect that even if we cut those people out of the data, weād still see an increase in the number of local groups over that time frame- so we canāt infer that EA is continuing to grow based on increase in local group numbers.
*Indeed, we should expect this because most people currently in the EA community (at least as measured by the EA Survey) are people who joined since 2015. In each EA survey, the most recent cohorts are almost always much larger than earlier cohorts (with the exception of the most recent cohort of each survey since these are run before some EAs from that year will have had a chance to join). See this graph which I previously shared, from 2019 data, for example:
(Of course, this offers, at best, an upper bound on growth in the EA movement, since earlier cohorts will likely have had more attrition).
----
do you think itās likely that there are about as many group members as before, spread across more groups? Or maybe there are more group members, but the same number of total people engaged in EA, with a higher % of people in groups than before?
Thereās definitely been a very dramatic increase in the percentage of EAs who are involved in local groups (at least within the EA Survey sample) since 2015 (the earliest year we have data for).
In EAS 2019 this was even higher (~43%) and in EAS 2020 it was higher still (almost 50%).
So higher numbers of local group members could be explained by increasing levels of engagement (group membership) among existing EAs. (One might worry, of course, that the increase in percentage is due to selective attrition, but the absolute numbers are higher than 2015 as well.)
Unfortunately we donāt have good data on the number of local group members, because the measures in the Groups Survey were changed between 2019-2020. On the one measure which I was able to keep the same (total number of people engaged by groups) there was a large decline 2019-2020, but this is probably pandemic-related.
University group members are mostly undergraduates, meaning they are younger than ~22. This implies that they would have been younger than 18 in 2017, and there was almost no one like that on the 2017 survey. And they would have been under 16 in 2015, although I donāt think we have data going back that far. I can think of one or two people who might have gotten involved as 15-year-olds in 2015, but it seems quite rare. Is there something Iām missing?
Iām not sure where you are disagreeing, because I agree that many people founding groups since 2015 will in fact have joined the movement later than 2015. Indeed, as I show in the first graph in the comment youāre replying to, newer cohorts of EA are much larger than previous cohorts, and as a result most people (>60%) in the movement (or at least the EA Survey sample[^1]) by 2019 are people who joined post-2015. Fwiw, this seems like more direct evidence of growth in EA since 2015 than any of the other metrics (although concern about attrition mean that itās not straightforward evidence that the total size of the movement has been growing, merely that weāve been recruiting many additional people since 2015).
My objection is that pointing to the continued growth in number of EA groups isnāt good evidence of continued growth in the movement since 2015 due to lagginess (groups being founded by people who joined the movement in years previous). It sounds like your objection is that since we also know that some of the groups are university groups (albeit a slight minority) and university groups are probably mostly founded by undergraduates, we know that at least some of the groups founded since 2015 were likely founded by people who got into EA after 2015. I agree this is true, but think we still shouldnāt point to the growth in number of new groups as a sign of growth in the movement because itās a noisy proxy for growth in EA, picking up a lot of growth from previous years. (If we move to pointing to separate evidence that some of the people who founded EA groups probably got into EA only post 2015, then we may as well just point to the direct evidence that the majority of EAs got into EA post-2015!)
[^1]: I donāt take this caveat to undermine the point very much because, if anything I would expect the EA Survey sample to under-represent newer, less engaged EAs and over-represent EAs who have been involved longer.
I think maybe I was confused about what you are saying. You said:
I think this applies to growth in local groups particularly wellā¦ While Iāve no doubt that many of the groups that have been founded by people who joined since 2015*, I suspect that even if we cut those people out of the data, weād still see an increase in the number of local groups over that time frame- so we canāt infer that EA is continuing to grow based on increase in local group numbers.
But then also:
Fwiw, this seems like more direct evidence of growth in EA since 2015 than any of the other metrics
In my mind, A being evidence of B means that you can (at least partially) infer B from A. But Iām guessing you mean āinferā to be something like āproveā, and I agree the evidence isnāt that strong.
DM: While Iāve no doubt that many of the groups that have been founded by people who joined since 2015*, I suspect that even if we cut those people out of the data, weād still see an increase in the number of local groups over that time frame- so we canāt infer that EA is continuing to grow based on increase in local group numbers.
BW: It sounds like maybe when you say āwe canāt infer that EA is continuing to grow based on increase in local group numbersā you mean āpart of the growth might be explained by things other than what would be measured by a change in number of groupsā? (Or possibly āincreasing group numbers is evidence of growth since 2015, but not necessarily evidence of growth since, say, 2019ā?)
I meant something closer to: āwe canāt infer Y from X, because weād still expect to observe X even if Ā¬Y.ā
My impression is still that we have been somewhat talking past each other, in the way I described in the second paragraph of my previous comment. My core claim is that we should not look at the number of new EA groups as a proxy for growth in EA, since many new groups will just be a delayed result of earlier growth in EA, (as it happens I agree that EA has grown since 2015, but weād see many new EA groups even if it hadnāt). Whereas, if I understand it, your claim seems to be that as we know that at least some of the new groups were founded by new people to EA, we know that there has been some new EA growth.
This seems like it could be true for some of the figures, but not all. Iād strongly expect ānumber of active EA groupsā to correlate with ānumber of total people engaged in EAā. The existence of so many groups may come from people who joined in 2015 and started groups later, but many group leaders are university students, so that canāt be the whole story.
In this case, do you think itās likely that there are about as many group members as before, spread across more groups? Or maybe there are more group members, but the same number of total people engaged in EA, with a higher % of people in groups than before?
I think this applies to growth in local groups particularly well. As I argued in this comment above, local groups seem like a particularly laggy metric due to people usually starting local groups after at least a couple of years in EA. While Iāve no doubt that many of the groups that have been founded by people who joined since 2015*, I suspect that even if we cut those people out of the data, weād still see an increase in the number of local groups over that time frame- so we canāt infer that EA is continuing to grow based on increase in local group numbers.
*Indeed, we should expect this because most people currently in the EA community (at least as measured by the EA Survey) are people who joined since 2015. In each EA survey, the most recent cohorts are almost always much larger than earlier cohorts (with the exception of the most recent cohort of each survey since these are run before some EAs from that year will have had a chance to join). See this graph which I previously shared, from 2019 data, for example:
(Of course, this offers, at best, an upper bound on growth in the EA movement, since earlier cohorts will likely have had more attrition).
----
Thereās definitely been a very dramatic increase in the percentage of EAs who are involved in local groups (at least within the EA Survey sample) since 2015 (the earliest year we have data for).
In EAS 2019 this was even higher (~43%) and in EAS 2020 it was higher still (almost 50%).
So higher numbers of local group members could be explained by increasing levels of engagement (group membership) among existing EAs. (One might worry, of course, that the increase in percentage is due to selective attrition, but the absolute numbers are higher than 2015 as well.)
Unfortunately we donāt have good data on the number of local group members, because the measures in the Groups Survey were changed between 2019-2020. On the one measure which I was able to keep the same (total number of people engaged by groups) there was a large decline 2019-2020, but this is probably pandemic-related.
University group members are mostly undergraduates, meaning they are younger than ~22. This implies that they would have been younger than 18 in 2017, and there was almost no one like that on the 2017 survey. And they would have been under 16 in 2015, although I donāt think we have data going back that far. I can think of one or two people who might have gotten involved as 15-year-olds in 2015, but it seems quite rare. Is there something Iām missing?
Iām not sure where you are disagreeing, because I agree that many people founding groups since 2015 will in fact have joined the movement later than 2015. Indeed, as I show in the first graph in the comment youāre replying to, newer cohorts of EA are much larger than previous cohorts, and as a result most people (>60%) in the movement (or at least the EA Survey sample[^1]) by 2019 are people who joined post-2015. Fwiw, this seems like more direct evidence of growth in EA since 2015 than any of the other metrics (although concern about attrition mean that itās not straightforward evidence that the total size of the movement has been growing, merely that weāve been recruiting many additional people since 2015).
My objection is that pointing to the continued growth in number of EA groups isnāt good evidence of continued growth in the movement since 2015 due to lagginess (groups being founded by people who joined the movement in years previous). It sounds like your objection is that since we also know that some of the groups are university groups (albeit a slight minority) and university groups are probably mostly founded by undergraduates, we know that at least some of the groups founded since 2015 were likely founded by people who got into EA after 2015. I agree this is true, but think we still shouldnāt point to the growth in number of new groups as a sign of growth in the movement because itās a noisy proxy for growth in EA, picking up a lot of growth from previous years. (If we move to pointing to separate evidence that some of the people who founded EA groups probably got into EA only post 2015, then we may as well just point to the direct evidence that the majority of EAs got into EA post-2015!)
[^1]: I donāt take this caveat to undermine the point very much because, if anything I would expect the EA Survey sample to under-represent newer, less engaged EAs and over-represent EAs who have been involved longer.
I think maybe I was confused about what you are saying. You said:
But then also:
In my mind, A being evidence of B means that you can (at least partially) infer B from A. But Iām guessing you mean āinferā to be something like āproveā, and I agree the evidence isnāt that strong.
I meant something closer to: āwe canāt infer Y from X, because weād still expect to observe X even if Ā¬Y.ā
My impression is still that we have been somewhat talking past each other, in the way I described in the second paragraph of my previous comment. My core claim is that we should not look at the number of new EA groups as a proxy for growth in EA, since many new groups will just be a delayed result of earlier growth in EA, (as it happens I agree that EA has grown since 2015, but weād see many new EA groups even if it hadnāt). Whereas, if I understand it, your claim seems to be that as we know that at least some of the new groups were founded by new people to EA, we know that there has been some new EA growth.