DAVID GREENE, HOST:
In the last few years we've had a big debate in this country about medical costs. Critics say financial incentives drive up costs and cause doctors and hospitals to deliver unnecessary treatments that are bad for patients. Well, there's new research now that ties incentives like that to the nation's soaring C-section rate. This is, of course, where babies are delivered via surgery.
NPR's social science correspondent Shankar Vedantam joins us often and he's here not to tell us about this. Shankar, welcome back.
SHANKAR VEDANTAM, BYLINE: Happy to be here, David.
GREENE: So money can play a role in the baby business.
VEDANTAM: It seems to, David. You know, look. In 1996, one in five babies in the United States were born via C-section. Today it's one in three. And in that same time period, childbirth costs have grown by as much as $3 billion. Lots of times, C-sections are warranted and necessary. But there is concern that some mothers are getting them when it's not needed.
I spoke with Erin Johnson. She's an economist at MIT. And along with her co-author, Marit Rehavi, they looked at how likely doctors were to get C-sections when they were mothers themselves. So Johnson tracked half a million births in California and a large number in Texas. Here's what she told me.
ERIN JOHNSON: We found that doctors are about 10 percent less likely to get C-sections. So obstetricians appear to be treating their physician patients differently than their non-physician patients.
GREENE: OK. Shankar, why are we comparing the rates of C-sections among moms who are themselves doctors, compared to moms who are not doctors?
VEDANTAM: You know, David, it's what I call the Car Mechanic Rule. Let's say you took your car in and the mechanic told you that you needed a transmission fluid flush. The only way that you can be sure that you're not getting ripped off by your mechanic is if you knew something about your car. You apply the same rule to medicine. Who are the patients who actually know whether a C-section is actually needed? It's other doctors.
GREENE: OK, so the difference we're seeing might be showing us where there are financial incentives at play. And this research is actually saying that doctors might be providing more C-sections when they're paid more.
VEDANTAM: Yes, but a doctor might not be thinking: Here's a chance to make an extra $200, so let me perform a C-section. It's much more subtle than that. It might even be happening at an unconscious level. In fact, Johnson finds that there is no disparity in C-sections when the C-sections are scheduled in advance; these tend to be cut and dried cases, there are clear medical guidelines.
The disparity comes about in unscheduled C-sections. That's where labor is attempted, it isn't going well, and the doctor now has to make a judgment call about whether to stop labor and do a C-section. It's in that kind of ambiguous situation where a judgment call is required that this kind of bias seems to flourish.
GREENE: Is this a pretty clear argument against providing physicians with financial incentives?
VEDANTAM: Not necessarily, David, because Johnson points out financial incentives are not the only incentives out there. In situations where doctors are paid a flat salary and there's no financial incentive, it turns out there are incentives related to time - because C-sections actually take more time for the doctor to do. And in those situations moms who are physicians end up getting more C-sections than mothers who are not physicians.
Presumably the mothers who are physicians are getting the C-sections because they're warranted. And some of the other women, for whom a C-section is warranted, aren't getting them.
GREENE: Shankar, I can imagine people hearing this and being really worried and not wanting money to play a role when they're thinking about procedures like C-sections and other things. What's the take home here? How should people deal with this?
VEDANTAM: Well, Johnson thinks the solution lies in patient knowledge and empowerment, that if you're going to a physician you should actually be asking a lot of questions and try and understand as much as you possibly can about what's going to happen to you when you give birth. In some ways it's the same as the Mechanic Rule, David. You really have to find a doctor whom you can really trust.
GREENE: Shankar, thanks as always.
VEDANTAM: Thanks, David.
GREENE: Shankar Vedantam regularly joins us to talk about social science research. And on Twitter you can follow him @hiddenbrain. You can also find this program @nprgreene and @morningedition.