Comment author: BenHoffman 13 May 2017 02:18:48AM 1 point [-]

If I try to steelman the argument, it comes out something like:

Some people, when they hear about the guide dog - tracheoma surgery contrast, will take the point to be that ameliorating a disability is intrinsically less valuable than preventing or curing an impairment. (In other words, that helping people live fulfilling lives while blind is necessarily a less worthy cause than "fixing" them.) Since this is not in fact the intended point, a comparison of more directly comparable interventions would be preferable, if available.

Comment author: PeterSinger 13 May 2017 11:53:35PM 5 points [-]

Why is the choice not directly comparable? If it were possible to offer a blind person a choice between being able to see, or having a guide dog, would it be so difficult for the blind person to choose?

Still, if you can suggest better comparisons that make the same point, I'll be happy to use them.

Comment author: saulius  (EA Profile) 13 May 2017 02:01:41PM *  4 points [-]

EDIT: this comment contains some mistakes

To begin with, I want to say that my goal is not to put blame on anyone but to change how we speak and act in the future.

His figure for the cost of preventing blindness by treating trachoma comes from Joseph Cook et al., “Loss of vision and hearing,” in Dean Jamison et al., eds., Disease Control Priorities in Developing Countries, 2d ed. (Oxford: Oxford University Press, 2006), 954. The figure Cook et al. give is $7.14 per surgery, with a 77 percent cure rate.

I am looking at this table from the cited source (Loss of Vision and Hearing, DCP2). It’s 77% cure rate for trachoma that sometimes develops into blindness. Not 77% cure rate for blindness. At least that’s how I interpret it, I can’t be sure because the cited source of the figure in the DCP2’s table doesn’t even mention trachoma! From what I’ve read, sometimes recurrences happen so 77% cure rate from trachoma is much much more plausible. I'm afraid Toby Ord made the mistake of implying that curing trachoma = preventing blindness.

What is more, Toby Ord used the same DCP2 report that GiveWell used and GiveWell found major errors in it. To sum up very briefly:

Eventually, we were able to obtain the spreadsheet that was used to generate the $3.41/DALY estimate. That spreadsheet contains five separate errors that, when corrected, shift the estimated cost effectiveness of deworming from $3.41 to $326.43. [...] The estimates on deworming are the only DCP2 figures we’ve gotten enough information on to examine in-depth.

Regarding Fred Hollows Foundation, please see GiveWell’s page about them and this blog post. In my eyes these discredit organization’s claim that it restores sight for $25.

In conclusion, without further research we have no basis for the claim that trachoma surgeries can prevent 400, or even 40 cases of blindness for $40,000. We simply don't know. I wish we did, I want to help those people in the video.

I think one thing that is happening is that we are too eager to believe any figures we find if they support an opinion we already hold. That severely worsens already existing problem of optimizer’s curse.


I also want to add that preventing 400 blindness cases for $40,000 (i.e. one case for $100) to me sounds much more effective than top GiveWell's charities. GiveWell seem to agree, see citations from this page

Based on very rough guesses at major inputs, we estimate that cataract programs may cost $112-$1,250 per severe visual impairment reversed [...] Based on prior experience with cost-effectiveness analyses, we expect our estimate of cost per severe visual impairment reversed to increase with further evaluation. [...] Our rough estimate of the cost-effectiveness of cataract surgery suggests that it may be competitive with our priority programs; however, we retain a high degree of uncertainty.

We tell the trachoma example and then advertise GiveWell, showing that GiveWell’s top and standout charities are not even related to blindness and no one in EA ever talks about blindness. So people probably assume that GiveWell’s recommended charities are much more effective than surgery that cures blindness for $100 but they are not.

Because GiveWell’s estimates for cataract surgeries are based on guesses, I think we shouldn’t use those figures in introductory EA talks as well. We can tell the disclaimers but the person who hears the example might skip them when retelling the thought experiment (out of desire to sound more convincing). And then the same will happen.

Comment author: PeterSinger 13 May 2017 11:47:33PM 7 points [-]

These are good points and I'm suitably chastened for not being sufficiently thorough in checking Toby Ord's claims,
I'm pleased to see that GiveWell is again investigating treating blindness: http://blog.givewell.org/2017/05/11/update-on-our-views-on-cataract-surgery/. In this very recent post, they say: "We believe there is evidence that cataract surgeries substantially improve vision. Very roughly, we estimate that the cost-effectiveness of cataract surgery is ~$1,000 per severe visual impairment reversed.[1]"
The footnote reads: "This estimate is on the higher end of the range we calculated, because it assumes additional costs due to demand generation activities, or identifying patients who would not otherwise have known about surgery. We use this figure because we expect that GiveWell is more likely to recommend an organization that can demonstrate, through its demand generation activities, that it is causing additional surgeries to happen. The $1,000 figure also reflects our sense that cost-effectiveness in general tends to worsen (become more expensive) as we spend more time building our model of any intervention. Finally, it is a round figure that communicates our uncertainty about this estimate overall. But it's reasonable to say that until they complete this investigation, which will be years rather than months, it may be better to avoid using the example of preventing or curing blindness." So the options seem to be either not using the example of blindness at all, or using this rough figure of $1000, with suitable disclaimers. It still leads to 40 cases of severe visual impairment reversed v. 1 case of providing a blind person with a guide dog.

Comment author: vollmer 11 May 2017 07:30:20PM *  4 points [-]

I agree with those concerns.

In addition, some people might perceive the "guide dogs vs. trachoma surgeries" example as ableist, or might think that EAs are suggesting that governments spend less on handicapped people and more on foreign aid. (This is a particularly significant issue in Germany, where there have been lots of protests by disability rights advocates against Singer, also more recently when he gave talks about EA.)

In fact, one of the top google hits for "guide dog vs trachoma surgery" is this:

The philosopher says funding should go toward prevention instead of guide-dog training. Activists for the blind, of course, disagree.

For these reasons, I suggest not using the guide dog example at all anymore.

The above article also makes the following, interesting point:

Many people are able to function in society at a much higher level than ever before because of service dogs and therapy dogs. You would think that’s a level of utility that would appeal to Singer, but he seems to have a blind spot of his own in that respect.

This suggests that both guide dogs and trachoma surgeries cause significant flow-through effects. All of these points combined might decrease the effectiveness difference from 1000x to something around 5x-50x (see also Why Charities Don't Differ Astronomically in Cost-Effectiveness).

Comment author: PeterSinger 12 May 2017 11:31:18PM 5 points [-]

I don't understand the objection about it being "ableist" to say funding should go towards preventing people becoming blind rather than training guide dogs

If "ableism" is really supposed to be like racism or sexism, then we should not regard it as better to be able to see than to have the disability of not being able to see. But if people who cannot see are no worse off than people who can see, why should we even provide guide dogs for them? On the other hand, if -- more sensibly -- disability activists think that people who are unable to see are at a disadvantage and need our help, wouldn't they agree that it is better to prevent many people -- say, 400 -- experiencing this disadvantage than to help one person cope a little better with the disadvantage? Especially if the 400 are living in a developing country and have far less social support than the one person who lives in a developed country?

Can someone explain to me what is wrong with this argument? If not, I plan to keep using the example.

Comment author: PeterSinger 12 May 2017 11:23:20PM 13 points [-]

Regrettably, I misspoke in my TED talk when I referred to "curing" blindness from trachoma. I should have said "preventing." (I used to talk about curing blindness by performing cataract surgery, and that may be the cause of the slip.) But there is a source for the figure I cited, and it is not GiveWell. I give the details in The Most Good You Can Do", in an endnote on p. 194, but to save you all looking it up, here it is:

"I owe this comparison to Toby Ord, “The moral imperative towards cost-effectiveness,” http://www.givingwhatwecan.org/sites/givingwhatwecan.org/files/attachments/moral_imperative.pdf. Ord suggests a figure of $20 for preventing blindness; I have been more conservative. Ord explains his estimate of the cost of providing a guide dog as follows: “Guide Dogs of America estimate $19,000 for the training of the dog. When the cost of training the recipient to use the dog is included, the cost doubles to $38,000. Other guide dog providers give similar estimates, for example Seeing Eye estimates a total of $50,000 per person/dog partnership, while Guiding Eyes for the Blind estimates a total of $40,000.” His figure for the cost of preventing blindness by treating trachoma comes from Joseph Cook et al., “Loss of vision and hearing,” in Dean Jamison et al., eds., Disease Control Priorities in Developing Countries, 2d ed. (Oxford: Oxford University Press, 2006), 954. The figure Cook et al. give is $7.14 per surgery, with a 77 percent cure rate. I thank Brian Doolan of the Fred Hollows Foundation for discussion of his organization’s claim that it can restore sight for $25. GiveWell suggests a figure of $100 for surgeries that prevent one to thirty years of blindness and another one to thirty years of low vision but cautions that the sources of these figures are not clear enough to justify a high level of confidence."

Now, maybe there is some more recent research casting doubt on this figure, but note that the numbers I use allow that the figure may be $100 (typically, when I speak on this, I give a range, saying that for the cost of training one guide dog, we may be able to prevent somewhere between 400 - 1600 cases of blindness. Probably it isn't necessary even to do that. The point would be just as strong if it were 400, or even 40.