the sum of local EA group facebook numbers might serve as a good proxy for the size of the EA movement per se
This is an interesting proposition, but one thing that will limit its usefulness, I think, is that lots of EAs are members of multiple local group Facebook groups, presumably either to show support or out of interest in their content. Aside from that, many members of the online groups appear to be not engaged in the local EA community (and perhaps not really engaged in EA at all): for example, EA London has around 2000 members of the Facebook group but many fewer people who are actively engaged and attend events and so.
It could also be combined with other metrics e.g. with impact (e.g. GiveWell donations, 80k Hours career changes) to assess communications effectiveness. with time (of the local EA team) and cost invested to achieve to assess operational effectiveness. If compared across local groups, the metrics would highlight local success stories and potentially where groups might need help.
The Local Groups Survey did this to some extent: measuring (self-reported) number of group members, Pledges, Career changes, funds raised or donations influenced, among other things. We don’t publicly release a breakdown of particular groups, of course, but we did look at the correlations between different variables and performance on different metrics. As you’d expect there was a fairly good correlation between success on different metrics, though with plenty of exceptions. I agree it would be valuable to have more systematic investigation of group performance of this kind to identify trends and where things seem to be working particularly well or not well.
This is an interesting proposition, but one thing that will limit its usefulness, I think, is that lots of EAs are members of multiple local group Facebook groups, presumably either to show support or out of interest in their content. Aside from that, many members of the online groups appear to be not engaged in the local EA community (and perhaps not really engaged in EA at all): for example, EA London has around 2000 members of the Facebook group but many fewer people who are actively engaged and attend events and so.
The Local Groups Survey did this to some extent: measuring (self-reported) number of group members, Pledges, Career changes, funds raised or donations influenced, among other things. We don’t publicly release a breakdown of particular groups, of course, but we did look at the correlations between different variables and performance on different metrics. As you’d expect there was a fairly good correlation between success on different metrics, though with plenty of exceptions. I agree it would be valuable to have more systematic investigation of group performance of this kind to identify trends and where things seem to be working particularly well or not well.