Thanks, Vaughn! This was indeed the intended meaning, but given that many interpreted it differently, I think the writing in the post could have been clearer. Hopefully the edits help clarify :)

Thanks, Joris! This is fixed :)

Thank you for all the feedback! I agree that the statement “would double your impact" was imprecise and as such, potentially misleading. While this statement was not intended to be taken as a literal (mathematical) doubling, but rather get at the idea that two new pledges is a rough doubling of one new pledge, this could have been made clearer. A more accurate phrasing would have been “could be seen as a rough doubling of one’s impact, assuming this person wouldn’t have otherwise heard about the pledge and wasn’t already donating” (assumptions I made but did not clarify well). Taking all of the feedback into account, I would be tempted to change the phrasing to the above and add the following footnote: 

Of course, impact is complex to measure, and it's possible these people might have been inspired to donate through other channels later on (and/or) that there were other agents or factors inspiring them in the first place. Additionally, we don't know if the people you might inspire to pledge are earning more or less than you or how likely it is that they will follow through on their pledge. So this isn't intended to imply a literal doubling, but rather an approximation of the potential value you could get by adding your name. Given that pledge awareness is extremely low in the general population, and the average amount people donate is around 2-3% of income, bringing awareness of the pledge to someone in the general population who would have been otherwise unlikely to hear about it and wasn't already donating -- if it resulted in that person signing the pledge -- could (in at least some cases) be seen as a doubling of your pledge’s impact. 

However, after further internal discussion we've decided to remove the "doubling" phrase entirely since we agree this is incorrect if looked at from a mathematical impact-calculating perspective, and we apologise for the imprecise language here. I've edited the post accordingly.

To respond to some of the points raised in the comments (note that these are my own views; I am not necessarily speaking for other GWWC team members):

 Owen --

“Conflation of "counterfactual money to high-impact charities" with "your impact"

Maybe even if it's counterfactually moved, you don't get to count all the impact from it as your impact, since to avoid double-counting and impact ponzi schemes it's maybe important to take a "share-of-the-pie" approach to thinking about your impact (here's my take on that general question), and presumably they get a lot of the credit for their giving”

I agree that the person pledging should get credit for their giving, but I don’t see this as contradictory to it potentially being a “doubling” of impact to inspire another person to pledge. Awareness of the pledge is extremely low outside of the EG/EA communities, so this statement comes from a place where we’re assuming it’s quite likely the person who was inspired would not otherwise have heard about the pledge or come to it on their own. They still get credit for 100% of their impact but it’s also the case that if you hadn’t inspired them to pledge, that impact likely wouldn’t have happened. I don’t see this as “double counting” because we aren’t trying to “sum” total impact but rather emphasise the potential for a pledger to have much more impact than just the value of their own donations. 

“Plus, maybe you do things which are importantly valuable that aren't about your pledge! It's at least a plausible reading (though it's ambiguous) that "double your impact" would be taken as "double your lifetime impact"

Absolutely! As this statement was made in the context of the value of pledge signing specifically, I did not think it was likely to be taken as doubling your impact more generally. However, this could have been better articulated by using the phrase “roughly doubling the impact of your pledge” which was the intended meaning.

 “As well as sharing credit for their donations with them, you maybe need to share credit for having nudged them to make the pledge with other folks (including but not limited to GWWC)”

Agree, and my response is similar to the point about sharing credit with them. I don’t think this negates the statement that a pledger could plausibly double their impact if a new pledger would not otherwise have been aware of the pledge.

 “As you say, their donations may not be counterfactual even in the short-term

Even if a good fraction of them are maybe from outside the community, that's still a fraction by which it reduces expected impact”

 Thank you for raising that. I do think I was speaking much too loosely (in part because, as Grace mentioned, it’s difficult to write for two audiences at once.) The statement did assume that the people who were inspired to pledge were from outside of the community, but I can see how this was unclear, especially given that I talk about inspiring people from inside the community (donors who were similarly sitting on the fence) later in the post.

 “Now, none of these points are blatant errors, or make me want to say "what were you thinking?!?". But I feel taken together the picture is that in fact there's a lot of complexity to the question of how impact should be counted in that case, and the text doesn't help the reader to understand that there's a lot of complexity or how to navigate thinking about it, but instead cheerfully presents the most favourable possible interpretation. It just has a bit of a vibe of slightly-underhand sales tactics, or something?”

 I agree that there is complexity here. This section of the post wasn’t intended to be an in-depth evaluation of how to count impact, but rather an argument for why there are plausibly good reasons to sign the pledge even if you already donate. As such, you are correct that it is presenting one possible interpretation/way to look at this. Though I had thought it was clear that I was presenting an argument, I definitely should have realised that the “misconception” framing could have made this feel like it was intended to be more of a factual statement andI agree with you that this was an oversight. (By the way, if you click on the survey, we don’t frame #4 as a misconception but rather ask if you were swayed or not swayed by the reasoning in the post.) I will mention that I'm a bit surprised to hear that you felt it had the vibe of underhand sales tactics, as this was absolutely not the intention. I hope the additional context above helps remove this impression!

Brad --

“Pledging may have some combination the effect of (a) actually increasing people's lifetime donations to effective charities and (b) causing people to advertise giving they already were going to do. To the extent that a pledge is b rather than a, getting someone to pledge the same amount as you is not double your impact.”

 Definitely agree with this. I should have made it clearer in the post that I was referring to inspiring people to take the pledge who wouldn’t otherwise have been donating. I do think b) would still increase your impact given some of the arguments about social cascades/norm setting, but certainly not double it, unless we limit the scope of “impact” to the impact of an extra name :)

 “Many of the people who you cause to become pledgers might have become pledgers later, thus you probably just accelerated their pledge, greatly decreasing your actual impact vs if you cause someone to pledge (and this pledge causes them to donate more rather than encompasses donation that would otherwise happen).”

I think this is actually fairly unlikely, especially if we are talking about people outside of the EG/EA community (which I agree should have been made clearer in the original post.) The awareness of the pledge is extremely low in the general public, so I think it’s highly unlikely (at least at this point in time) that someone in the general public would have found about it down the line anyway.

 “There's a possibility that you could anchor someone to donate less. Potentially someone could see your celebrated 10% pledge and view that as adequate, lowering their donations. Here, there is a risk of harm from the pledge.”

 While this is certainly a possibility, given that (while this varies by income level and country) the average person donates around 2-3% of their income, I think it’s much more likely that the pledge would increase someone’s donations rather than cause them to donate less.

Kirsten --

“A bit of feedback, since this is a sales piece and I do actually like Giving What We Can:

Saying that there's no good reason not to pledge if you're already donating 10% sits really poorly with me. It feels insulting that you've decided that my reasons aren't good enough and must be only based misunderstandings.

Even if my only reason not to pledge is that I've thought about it carefully and decided I don't want to, shouldn't that be enough?”

 Thank you for voicing this. The post was framed as 5 “misconceptions” to pull everything together, but (as I mentioned to Owen) if you look at the survey, you’ll see that we don’t view #4 as a misconception but rather a matter of opinion. The question instead asks if you agreed or disagreed with the statement and if you were swayed or not swayed by the reasoning in the post. We certainly aren’t trying to attack anyone’s reasons or pressure anyone into doing something they don’t feel is right for them; rather, we are trying to present an argument for taking the pledge if you are already donating. I went into this a bit more in my response to Owen – I hope that added context at least helps clarify that this was not intended as an attack or dismissal of anyone’s reasoning. I’ve also edited the language of the misconception to say “there is no plausibly good reason” and added a note clarifying that we don’t think it’s a “misconception” not to agree with the reasoning presented.

Thanks for writing this! I always wonder how often to call about the same issue. Did you find anything about this in your research?