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Marius comments on Efficient Charity: Do Unto Others... - Less Wrong

130 Post author: Yvain 24 December 2010 09:26PM

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Comment author: Marius 25 December 2010 01:39:51PM *  26 points [-]

I happen to administer a lot of blood to my patients, so let me answer some of the factual questions.

  1. The way they calculate "up to 3 lives" is in the most trivial way: blood you donate is fractionated into red cells, plasma, and platelets. Each of those may go to a different recipient.

  2. All blood administered to patients comes from voluntary, uncompensated donations. Plasma used in research studies may be compensated, but may not be transfused. This is the most important factor keeping our blood supply safe, and is far more effective than laboratory testing alone.

  3. Given that blood banks need to keep a sufficient store of blood available of each type, rarer blood types are generally in greater need than, say, A After all, a larger proportion of blood of those types must be discarded. O blood is obviously highly useful in trauma situations, and is therefore in high demand as well.

  4. The distribution of donors' and recipients' blood types should not be assumed to be equal: people with blood type A are significantly more likely to donate than people with blood type B. This exacerbates the discrepancies due to point 3.

  5. The number of lives saved can be calculated in two ways:

a. the feel-good way. Every time a physician gives a unit of blood to a patient e does so believing it is a life-saving procedure. So if 3 units are given the patient's life was saved 3 times in rapid succession. (You have to be willing to save a life multiple times, because that's the analysis we're using for the rest of this discussion: multiple mosquito nets saved the same kid's life multiple times over his lifetime; that same kid was then saved by anti-diarrheal treatments; etc. The same analysis belongs here). Now, we subtract the number of patients who die, but that's a small number. So 26 million transfusions/16 million donations = 1.6 lives saved per donation.

b. the marginal way. Donations are currently sufficient for usage; we benefit in three ways from more donations. First, we can be slightly more profligate with trauma patients who have a low survival chance; this saves a minimal number of lives. Second, fresher blood is associated with better outcomes than older blood; the extent of this effect is unknown but is an area of current research interest. The calculation would have to look at the likelihood that your donation reduced the average shelf age of the blood being administered times the survival improvement from the fresher blood. Third, blood from multiparous women is associated with ARDS; an increase in donation would allow us to stop using it.

Comment author: Alicorn 25 December 2010 01:58:43PM 7 points [-]

people with blood type A are significantly more likely to donate than people with blood type B

I've donated blood a few times and I'm type A+. Why is it that B's are less likely to donate, or is that unknown? Are my donations likely to be marginally useless?

I have mostly donated blood in the past for signaling reasons, conversational high ground, and a vague desire to match the 15-gallon mark that my grandfather got his name in the paper for. There's a plaque of the newspaper mention in my grandma's house and I've been looking at it my whole life. Also I figure the Red Cross will let me know if I come down with one of the diseases they screen for, and it's a free way to get my iron levels checked (attempting to donate blood was how I found out I was anemic in the first place). These reasons aren't likely to evaporate if I find that I have been saving only tiny fractions of expected lives, but I would probably endure less inconvenience in order to donate for only these reasons as opposed to these reasons on top of lifesaving.

Comment author: Marius 25 December 2010 05:49:32PM 9 points [-]

Your donations are not marginally useless! (unless you've been pregnant a couple times - in that case, consider stopping).

The reason for the discrepancies in donation rates between types A and B is both simple and complex: ethnicity. In the interests of safety (avoidance of Hepatitis C, HIV, etc) we've set up a system that subtly encourages certain types of donors and discourages others. The system is not racist per se, but it is most effective in obtaining donations from white, middle-aged, middle-class males.

Regarding signaling reasons: we are obviously very afraid of blood donated for signaling purposes. Accordingly, we do not allow people to donate to their relatives except under very unusual circumstances. Additionally, we give people an "out" by checking a box which tells the center to draw and discard their blood. That way people who fear they may be high-risk donors can get the social approval of donating without harming any patients.

Comment author: Alicorn 25 December 2010 07:09:59PM 4 points [-]

unless you've been pregnant a couple times - in that case, consider stopping

I've never been pregnant, but what is it about multiple pregnancies that renders the blood non-preferred?

Comment author: Eliezer_Yudkowsky 25 December 2010 07:18:25PM 3 points [-]

Obvious guess: Your blood then contains antibodies to the blood type of your babies.

Comment author: Marius 25 December 2010 07:25:27PM 2 points [-]

Essentially this. The A/B/O blood groups represent the most relevant antigens in human blood. There are a host of others (Rh, Duffy, Kell, etc.) which typically create only minor problems in a transfusion and which can be ignored in an emergency. But a person who has been exposed to allogeneic blood via multiple transfusions or pregnancies becomes more likely to develop antibodies to some of these antigens. The donor's antibodies or white cells can react to the person being transfused, causing lung damage.

Comment author: wedrifid 25 December 2010 08:48:28PM *  3 points [-]

There are a host of others (Rh, Duffy, Kell, etc.) which typically create only minor problems in a transfusion and which can be ignored in an emergency.

In the case of the Rhesus factor it should be noted that it is minor once and then only minor for males. Being thereafter unable to safely give birth to healthy Rh+ children is definitely not a minor consequence even if it is better than 'probably going to die today'. (Unless, I suppose, you happen to some Rh+ antiserum lying around but no Rh- blood, which will usually avoid the future difficulties.)

Comment author: Marius 25 December 2010 10:34:27PM 6 points [-]

I use "minor" differently than you do, to mean "unlikely to cause death". Obviously cross-matched blood is always preferable for a variety of reasons (including possible infertility, in the case of young females).

I would avoid RhoGam in the case of a patient who needs a RBC transfusion, incidentally. It would be unlikely to be safe or effective.

Comment author: shokwave 26 December 2010 09:50:13AM *  4 points [-]

I use "minor" differently than you do, to mean "unlikely to cause death".

I would like to express that my approval of this phrase extends beyond the capacity of upvoting and into the capacity of a comment expressing approval.

Comment author: wedrifid 26 December 2010 10:04:43AM *  1 point [-]

I use "minor" differently than you do, to mean "unlikely to cause death".

And having both your arms removed is "Just a flesh wound!".

Comment author: TobyBartels 26 December 2010 08:04:40AM *  0 points [-]

Oops, I see that this has already been asked.


we've set up a system that subtly encourages certain types of donors and discourages others

While we've got you here, can you explain why gay men cannot donate? This upsets a lot of gay people that I know.

I understand that it's easier to catch STDs (not just HIV/AIDS) from a man than from a woman. But the current U.S. rule (A man cannot donate if he's had sex with a man; a woman cannot donate if she's had sex with a man who's had sex with man.) is lopsided.

The even-handed rule that you cannot donate if you've had sex with a man would keep the supply safe without having to rely on people's being able to trust their partners. But it would keep most women from donating, so maybe it's not worth it. The even-handed rule that you cannot donate if you've had sex with man who's had sex with a man would still keep out most gay men, but it would probably help to heal the rift.

Comment author: Alicorn 26 December 2010 01:11:13PM 1 point [-]

The even-handed rule that you cannot donate if you've had sex with man who's had sex with a man would still keep out most gay men

If a man is gay and sexually active, he's almost certainly had sex with a man who's had sex with a man, even if the men he has had sex with has only had sex with him. I don't see how this phrasing of the rule would be an improvement.

Comment author: TobyBartels 28 December 2010 12:17:07AM *  0 points [-]

My phrasing was unclear; make it "if you've had sex with man who's previously had sex with a man (other than you)". There wouldn't be any point in forbidding me from donating (if I'm male) because the man that I've had sex with has had sex with me!

This change would include more people; it includes monogamous gay male couples who began their relationship as virgins (as well as some other people). Not many more, but it makes it clear that the blood collector is only willing to trust you and your partners, no further.

Frankly, the first even-handed rule (no sex with a man, period) makes more sense to me. Why should the blood collector trust that I know (if I'm a woman) whether all of the men that I've had sex with have had sex only with women? (No doubt many women are donating contrary to guidelines because they don't know this about their partners.) But because this would cut the potential donor pool in half, the blood collector is basically forced to trust me about my partners too.

In fact, the blood collectors trust women to know the sexual history of their partners, but not men. They are not asking everybody the same questions.

Comment author: TobyBartels 30 December 2010 07:36:05AM *  0 points [-]

Another possible solution, not even-handed, but more honest: Just don't ask women anything about the subject.

The idea that a person can be trusted to know about their partners' partners is preposterous; no other question (in the U.S.) asks the donor about other people's behaviour, and for good reason. Instead of half-assedly trying to be even-handed about it, just admit what they're doing: ruling out men who've had sex with men, because many of their partners will have had sex with other men, and so on back (in many cases) a long way; but accepting women who've had sex with men, because most of their partners won't have had sex with men, stopping the transmission-from-men sequence.

I'm confident that they already accept blood from most women who've had sex with men who've had sex with men (because the women don't know this about their partners), and they are surely aware of this (if I am correct) fact. So why are they asking questions of people who don't actually know the answers?

Gay people will still be upset that they can't donate, but I at least would be more willing to trust that the blood collectors are actually making an honest decision.

Comment author: TheOtherDave 30 December 2010 05:35:54PM 0 points [-]

Mostly, my faith in the quality of the blood supply derives from what testing they're doing to the blood, not from what unenforceable policies they're suggesting to the donors.

I'd actually be surprised if the latter significantly affected the quality of the blood.

Mostly, I think the problem they are a solution for is maintaining public confidence in the blood supply. Which I acknowledge is an important problem. And it may well be that being perceived as excluding gay men and their partners is a better solution to that problem than anything else they might do; I don't know.

That said, if I'm wrong and these policies really do solve a problem related to the blood supply, yet another possible solution is: don't allow people who have had unprotected sex to donate.

Or, if that's too big a chunk of your potential donor base, make it people who have had unprotected sex outside of a monogamous relationship.

Comment author: shokwave 26 December 2010 01:54:35PM *  0 points [-]

The original rule bars 'a man who has had sex with a man' - X - and then any women who've had sex with X. It's a logical phrasing but unfortunately X maps exactly onto "gay man", so it feels like gay men are being specifically targeted. The rephrasing mollifies that sense of targeting without, as far as I can tell, changing the included or excluded people.

The original phrase is even-handed, however. If you overspecified an even-handed rule and said "1) You cannot donate if you're a man who has had sex with a man who has had sex with a man, and 2) you cannot donate if you're a woman who has had sex with a man who has had sex with a man" - ie, prevent "man who has had sex with a man" from coming into sexual contact with any donor - you could reduce 1) down to "man who has had sex with a man" (it logically implies three, four, and so on iterations). This, therefore, reduces down to the actual rule they have in place.

Comment author: wedrifid 25 December 2010 02:41:27PM *  5 points [-]

Every time a physician gives a unit of blood to a patient e does so believing it is a life-saving procedure. So if 3 units are given the patient's life was saved 3 times in rapid succession. (You have to be willing to save a life multiple times, because that's the analysis we're using for the rest of this discussion: multiple mosquito nets saved the same kid's life multiple times over his lifetime; that same kid was then saved by anti-diarrheal treatments; etc. The same analysis belongs here)

There are not many times I see a line of reasoning and have to reject it at every single step. Apart from being conceptually absurd the very thought is morally objectionable. It totally devalues the value of 'saving a life' to the point of utter meaningless. How could that ever make someone 'feel-good'?

Comment author: Vaniver 25 December 2010 03:13:26PM 12 points [-]

It totally devalues the value of 'saving a life' to the point of utter meaningless.

Which part? I thought that started silly (it's explaining the logic behind a non-profit's puffery, did you expect it to be rigorous?) but then got better. The idea of "saving a life" is pretty meaningless when you poke at it- it's all just lifespan extension. And so the idea that each emergency treatment extends lifespans by the 'natural span of a life' is silly. If someone would die if they don't receive a unit of blood at 50 separate occasions on their life, should each transfusion get the full moral weight of saving a life? If so, we just gave this person 50 lives. If not, then we need to abandon the language of "saving a life" and talk about "extending a lifespan" (because we can say those units of blood each added a year to the person's life, for example).

Comment author: datadataeverywhere 25 December 2010 02:02:48PM 4 points [-]

Thanks, this is exceptionally informative.

I didn't realize that donations were sufficient for usage. Is this barely maintained by calling people when blood supplies are low, or does blood regularly get thrown out, or is there some other reason that supplies closely match need?

Comment author: Marius 25 December 2010 05:34:31PM 6 points [-]

A combination of the above. We have a core group of donors who can be called in emergency situations, we increase the intensity of blood drives when supplies are low, we reduce marginally-beneficial uses of blood when supplies become low, and we are better able to discard the oldest least-effective blood whenever supplies increase.

We are likely to face challenges in meeting future need. The cohort that most regularly donates blood is aging...

Comment author: [deleted] 25 December 2010 07:46:15PM 0 points [-]

We are likely to face challenges in meeting future need. The cohort that most regularly donates blood is aging...

I'm assuming you are from the US, do you think the same is true for other countries? Also which demographic are you referring too?

Comment author: wedrifid 25 December 2010 08:24:16PM 3 points [-]

I'm assuming you are from the US, do you think the same is true for other countries? Also which demographic are you referring too?

I'm more interested in the cohort that isn't aging. What is their secret? A new and improved Calorie Restricted diet? Perhaps that explains their inability to generate sufficient excess blood for donation.

Comment author: Will_Sawin 25 December 2010 09:28:03PM 2 points [-]

They could also be brain uploads, which would also explain the inability.

Comment author: wedrifid 25 December 2010 09:58:43PM 2 points [-]

Good point. I wonder if they would consider donating CPU time instead!

Comment author: TheOtherDave 25 December 2010 06:04:04PM 1 point [-]

Thanks for data!

Only vaguely relatedly: if you have pointers to (or are willing to synthesize) a reliable calculation of expected lives-saved/deaths-caused by maintaining or discarding the existing Red Cross policies about who is "allowed" to donate blood, especially the relatively controversial ban on male donors with homosexual acts in their sexual history, I would be interested.

Full disclosure: I do have a personal/emotional stake in this question, but I really really don't want to set off a political/ethical conversation about it. I'm asking it here because, as with a lot of politically charged topics, the arguments I've found on both sides are mostly a case of framing the question so as to give the answer one wants to give, rather than so as to answer the question that was asked, and I'm looking for a more objective analysis.

Comment author: datadataeverywhere 25 December 2010 06:49:02PM 8 points [-]

I also wanted to ask this question.

Giving blood is important to me. It is so important that I have chosen not to pursue relationships with other men in order than I can continue to give blood without lying to do so. I expect that sooner or later, I will choose otherwise, and a sexual relationship will be important enough to me to sacrifice my ability to ever give blood again, and this distresses me.

I can accept that the risks of HIV may be high enough to make this a reasonable choice on the part of United Blood Services / Red Cross. However, I would like to be quite sure that this is the case, or to be told that my blood isn't as important as I previously though it was. I was previously giving blood on the impression that each donation saves around a twentieth of a life; this thread doesn't change that estimate enough for me to feel like I can stop donating in good conscience.

Comment author: Eliezer_Yudkowsky 25 December 2010 07:08:44PM 16 points [-]

Giving blood is important to me. It is so important that I have chosen not to pursue relationships with other men in order than I can continue to give blood without lying to do so.

On the margins, I expect that each marginal pint of blood saves only a very small fraction of a life. As several readers pointed out, this doesn't mean that we should ordinarily be calculating on the margins, since it's not like you can use a pint of blood for something else instead; in terms of moral credit, you should think of yourself as part of a reference class of people who all choose to donate blood for around the same reasons, and who all get an equal share of the lives saved.

However, the Red Cross has already decided that they're willing to X out the entire homosexual community, and I would expect the reference class of those who refrain from sexual activity in order to continue donating blood to be small, and I would guess that if this entire reference class refrained from donating blood, not a single additional life might be lost.

Modern-day hospitals are not, so far as I know, blood-limited. They need a routine flow of blood in order to routinely save lives. They do not need more blood to save more lives. That's the impression I got, anyway; some quick Googling even said that they usually have enough blood to just use O-negative instead of matching types.

I hate to say this, but I think you're making the wrong sacrifices here. I estimate a very high information value for further investigation on your part; I would expect it to show that you were safe to stop donating blood and resume sexual activity without costing anyone one-twentieth of a life. If you're really feeling guilty or worried, resume sexual activity and send a donation to the Singularity Institute as a carbon offset. If you can speed up a positive Singularity by one minute that works out to around 100 lives, never mind increasing the probability.

Comment author: datadataeverywhere 25 December 2010 11:45:12PM 6 points [-]

I think I was accidentally misleading by failing to add that I'm bisexual. Not giving blood reduces my pool of potential romantic partners by roughly 10%, and doesn't prevent me from having fulfilling relationships. I don't think I would abstain from sex in order to give blood even if I knew I could save a life with each donation. Even if that's an incredibly selfish decision, I'm just not that good a person.

Regardless, the support of everyone who replied is very much appreciated.

Comment author: katydee 26 December 2010 12:42:25AM *  0 points [-]

...technically, doesn't speeding up a negative singularity also save lives-- the lives of those who would otherwise have been born and then killed but were instead never born and therefore couldn't be killed? In fact, I think speeding up a negative singularity actually "saves" more lives than speeding up a positive one using this calculation-- a quick Google search indicates ~250 people are born every minute and ~100 people die every minute.

Comment author: Vaniver 26 December 2010 12:50:20AM 6 points [-]

Replace "save lives" with "extend lifespans." All the math will suddenly start working out better.

Comment author: soreff 26 December 2010 05:19:32AM 2 points [-]

Agreed, I retrospect I should have phrased the original question in terms of QALYs or some similar metric.

Comment author: Desrtopa 27 December 2010 11:58:07PM 3 points [-]

In a fairly meaningful sense, no life has ever been saved before. Nobody has actually been prevented from dying yet. A positive singularity could change that.

Comment author: Marius 25 December 2010 07:39:42PM 4 points [-]

I believe you can make an easier calculation: change the denominator from lives to units of blood. How much effort/money/social capital would it take you to convince one more person to donate one more unit? [ignore the cost to that person, as it's likely zero or slightly beneficial]. Calculate the effort it therefore would take you to replace yourself as a donor while keeping the blood supply constant; this should serve as an upper bound for the self-sacrifice you should make in terms of sexual restraint.

Comment author: datadataeverywhere 25 December 2010 11:49:22PM 1 point [-]

You make an excellent point. I clarified that the sexual restraint required is not as great as it may seem, but convincing other people to donate regularly (I have done so at least twice in my life) is still much less of a sacrifice.

Comment author: TheOtherDave 25 December 2010 08:59:43PM 2 points [-]

(nods) For me, it's not a pragmatic question of whether I donate or not: after ~20 years in a mutually monogamous relationship, I am confident that my donating blood reduces the percentage of infected blood in the supply, regardless of my gender, and that's the metric that matters.

But I spent some time trying to make sense of the arguments pro and con, a few years back, and mostly came to the conclusion that I didn't trust anyone's arguments.

It is certainly true that if you divide the community of potential donors into two groups, and the frequency of blood-born pathogens is higher in group A than group B, and your filtering mechanisms aren't 100% reliable, then the blood supply is N% safer if you remove group A from potential donors.

It is equally certainly true that you can do that division in thousands of different ways, and each way of doing that division gets you a different N.

I was hoping to find a comparison of estimated Ns for different plausible policies, and perhaps a recommendation for the best policy.

What I found instead was that defenders of the existing policy were making the first argument and saying "See? The policy makes the blood supply N% safer! We have to keep doing it, to do otherwise would be unsafe!" while at the same time disregarding questions about how large N actually was (i.e.., how many lives were actually at stake? 1000? .001? Somewhere in between?) and whether a different policy might get you a much larger N, while opponents of the policy were disregarding the first argument altogether.

Comment author: wedrifid 25 December 2010 09:20:30PM 0 points [-]

But I spent some time trying to make sense of the arguments pro and con, a few years back, and mostly came to the conclusion that I didn't trust anyone's arguments.

My conclusion is somewhat related. I have no particularly good reason to believe that I am better able to establish blood donation and usage policy than the Red Cross or the medical practitioners. I just give them my blood and they can use it or not as they see fit. I'd do it just for the health benefits anyway.

Comment author: TheOtherDave 25 December 2010 09:53:40PM 1 point [-]

For my own part, I appreciate that the Red Cross (and etc.) is trying to satisfy multiple constraints, only one of which is the actual safety of their blood supply, and I don't object to that. But the constraints that apply to them in articulating a policy don't necessarily apply to me in donating blood.

Comment author: wedrifid 25 December 2010 09:57:17PM *  1 point [-]

On the other hand you have constraints that they do not have, not least of which is the lack of scaling benefits for your research and decision making efforts.

We are left with an optimal approach of considering what we know of our own blood that the collection agency does not (or is forbidden from discriminating on). We can approximate whether this knowledge would make the blood more suitable or less. Only if 'less' do we need worry about how significant that extra knowledge is.

Comment author: TobyBartels 30 December 2010 07:44:39AM 0 points [-]

We also need to worry if the answer is ‘more’ and because of that we decide to lie on the answer form so that we can donate.

I kind of get the impression that TheOtherDave is doing that, or at least would condone it under circumstances very much like his.

Comment author: TheOtherDave 30 December 2010 05:25:37PM *  0 points [-]

I don't do it, mostly because I'm so irritated by the policy that I've worked my way into a completely counterproductive "F--k it, then, donate your own f--king blood, see if I care" kind of sulk about it. I'm not proud of this, but there it is.

Yes, I condone it... indeed, I endorse it... in situations very much like mine.

Comment author: JoshuaZ 25 December 2010 06:57:51PM 0 points [-]

They aren't assessing that risk in a logical fashion. If they were, they would have similar restrictions on donation by ethnic group. (It is possible that the Red Cross would like to do that also but knows that it is political unfeasible.)

Comment author: CarlShulman 26 December 2010 12:35:30AM 4 points [-]

Will Saletan has an article on this.

Comment author: Perplexed 25 December 2010 03:02:58PM 1 point [-]

Thx.

All blood administered to patients comes from voluntary, uncompensated donations. Plasma used in research studies may be compensated, but may not be transfused. This is the most important factor keeping our blood supply safe, and is far more effective than laboratory testing alone.

This article on the ethics and pragmatics of blood source - compensated vs uncompensated - was fascinating, IMO. Though it may be somewhat out-of-date.