Does Nudging Explain Differences in Organ Donation Rates?

by Henry Farrell on July 10, 2011 · 7 comments

in Other social science

It’s great that David Brooks is taking to the NYT to defend NSF funding for the social sciences. This is not the kind of cause that NYT op-ed writers usually take up. Even so, one of the examples of social science in action that he points to is not nearly as clear-cut as he suggests.

Brooks argues:

When you renew your driver’s license, you have a chance to enroll in an organ donation program. In countries like Germany and the U.S., you have to check a box if you want to opt in. Roughly 14 percent of people do. But behavioral scientists have discovered that how you set the defaults is really important. So in other countries, like Poland or France, you have to check a box if you want to opt out. In these countries, more than 90 percent of people participate. This is a gigantic behavior difference cued by one tiny and costless change in procedure.

Contra Brooks, there is no ‘gigantic behavior difference’ cued by a default assumption of opt-in (or, as it is called in the relevant literature, ‘presumed consent’). As Kieran Healy discusses in this 2006 article, presumed consent countries have transplantation rates that are only a little bit higher than informed consent countries. Moreover, the most plausible explanation for this difference isn’t differences in default choices. It’s differences in the quality of organization:

Presumed-consent countries do in fact perform a little better on average than informed-consent countries. I have argued that this is not because of any direct effect of the law on individual choices. Rather, countries with presumed-consent laws are more likely to have paid close attention to the social organization of their transplant systems. High yield cases like Spain and Italy stand out not because their legal systems mandate a different kind of choice for donors, nor because they offer some special incentives for donor families or next of kin. Instead, they have invested effectively in the logistics of the transplant system: they put more staff on the ground, trained them better (especially in the crucial process of requesting consent from families), and improved coordination between the different actors and agencies in the procurement process. Recent research shows that similar reforms may boost donation rates in United States organ procurement organizations.

The just-so story seems to be traceable back to Dan Ariely who notably relies on a relationship between opt-in/opt-out regimes and survey data on whether people would be hypothetically willing to donate organs (this, presumably, is what Brooks is referring to as ‘participation’). But it would appear that this hypothetical willingness does not translate into large scale differences in actual observed behavior. However, the stylized story has become quite widespread among pop-sociology/economics writers, quite likely because it is both appealingly counter-intuitive, and fits neatly with a broader story about the beneficial consequences of policy nudges. Interestingly, blood donation patterns have been the subject of a similar set of controversies, between libertarians who argued for market solutions, and lefties who argued that voluntary donations would be driven out by a market logic (again, reality is more complicated than either of those stylized stories would suggest).


Andrew Gelman July 10, 2011 at 6:54 pm


Here is some more background: Eric Johnson and Dan Goldstein, who did the study that was cited, are research psychologists, and in their paper they discuss the rate of donation (which they estimate to increase from 14 to 16 per million under presumed consent).

So, yes, blame Ariely for the pop-sociology. But don’t blame Johnson and Goldstein: they were following good research practice and looking for large immediate effects and smaller distant effects. They found defaults to be important in how people frame decision problems, and I think that’s important even if it’s been misunderstood by the Arielys of the world.

will July 10, 2011 at 8:37 pm

“The just-so story seems to be traceable back to Dan Ariely who notably relies on a relationship between opt-in/opt-out regimes and survey data on whether people would be hypothetically willing to donate organs”

Shouldn’t actual participation rates show a larger gap than hypothetical preferences if the “nudge” works? Surely the thesis is that people neglect to check the box in an opt-in regime (or possibly, don’t bother to exempt themselves in an opt-out regime)–not that people’s actual preferences are affected by opt-in vs. opt-out. I personally was not a donor on my first driver’s license, simply because I forgot to check the box.

C. Leener July 10, 2011 at 10:51 pm

Actually, the article Brooks and Ariely refer to, the Johnson / Goldstein Science piece “Do Defaults Save Lives?”, is an econometric study based on ten years of data across all European countries, combined with lab studies. It and two other independent econometric studies, which all control for “the quality of organization”, all find the same thing: a default effect on the order of a 15% to 50% increase in actual transplantation operations.

Mark July 10, 2011 at 10:59 pm

Beyond organ donation, status quo biases are profoundly influential in a number of domains we care about- Madrian and Shea’s 2001 study (published in QJE) of default contributions demonstrated a drastic improvement in 401k contribution rates; Benartzi and Thaler’s Save More Tomorrow plan similarly expanded participation in savings programs.

While I’m a bit skeptical of this reinterpretation of the Johnson/Goldstein data, I think the larger point is that behavior research can have a profound impact on public policy, while still remaining (generally) appealing to a broad swath of the political spectrum.

Henry Farrell July 11, 2011 at 12:06 am

C. Leener – I’ve revised the post to include a link, as it should have done initially, to Kieran Healy’s specific take on the ways in which Ariely uses Johnson/Goldstein, and alternative presentation of the data on actual donation rates.

Henry Farrell July 11, 2011 at 12:10 am

Also see this post for further discussion.

Kieran July 11, 2011 at 5:18 am

Just for the record, I think it’s pretty clear from my paper on this and from the blog post I originally wrote about this that I don’t blame Johnson & Goldstein for anything, and indeed say explicitly that I like their paper. I do think Henry’s right that the Freakonomics post by Ariely seems to be the origin of a way of misunderstanding things about opt-out laws—that elides the difference between signing up as a donor and actually becoming a cadaveric donor upon one’s death—that has by now become very widespread, and been repeated in a bunch of different places in print.

Comments on this entry are closed.

Previous post:

Next post: