Select Publications

Singh, M. (2021). Heuristics in the delivery room. Science, 374(6565), 324-329.


Clinical decisions made in the delivery setting are often made under high pressure, great uncertainty, and have serious consequences for mother and baby. Theories of decision-making suggest that individuals in such settings may resort to using “heuristics”, or simplified decision-rules, to aid complex decision-making. This study investigates whether physicians’ delivery-mode decisions (i.e., when to perform a vaginal vs. a cesarean) are influenced by such a heuristic. Electronic health record data spanning 86,000 deliveries suggests that, if the prior patient had complications in one delivery-mode, the physician will be more likely to switch to the other -- and likely inappropriate -- delivery-mode on the subsequent patient, regardless of patient indication. There is evidence that this heuristic has small, suboptimal effects on patient health.

Press: Choiceology (podcast), Random Acts of Medicine (book), New York Times Upshot, Freakonomics MD, Tradeoffs Newsletter, LA Times, The Conversation, Quartz, Reuters Health, and 41 others

Click HERE for an ungated link to the paper

Results as a limerick

A patient has a bad reaction,

To the Doc’s deep dissatisfaction, 

Feeling unfit,

Doc cries out, "Oh sh*t!"

And switches her medical plan of action.

Working Papers

How Power Shapes Behavior: Evidence from Physicians (with Steve Schwab) (R&R at Science)


Power, defined as the asymmetric control of valued resources, affects most human interactions. Yet there is little observational evidence on how power affects behavior and resource allocation. We examine this question using the power differential in the doctor-patient encounter: while it favors the physician in the clinical setting, powerful patients may be able to reduce this asymmetry and so influence physician behavior. We exploit the quasi-exogenous assignment of 1.5 million patients to physicians in US military emergency departments, using the difference in their military ranks to measure their power differential. We find that power confers nontrivial advantage to its possessor: “high-power” patients (those who outrank their physician) receive greater physician effort and have better outcomes than equivalently-ranked “low-power” patients. We document other suggestive results: (i) within-physician effort is higher for patients recently promoted than those about to be promoted, (ii) low-power patients suffer when their physician concurrently cares for a high-power patient, and (iii) rank-based power dynamics vary predictably by doctor-patient concordance on race and sex. While power-driven variation in behavior is often undesirable, it is especially concerning in healthcare where it can harm society's most vulnerable patients.

Press: Tradeoffs Newsletter, Random Acts of Medicine (blog)

Results as a limerick

Is power too beckoning a call?

Since doctors are human after all,

We took the military's example,

Rank predicted care in our sample,

The mighty were heeded o'er the smal. 

Do Physicians Improve More from Positive or Negative Feedback? (with Jacob Zureich) (Second-round R&R at Management Science)


We use clinical data on over 240,000 surgeries and several quasi-experimental methods to examine how physicians respond to the surprise release of a quality "report card". Such feedback interventions are commonly used to encourage physicians to improve performance, yet show limited evidence of success. Our results show that these limited effects mask heterogeneous behavioral responses to feedback valence. In particular, physicians improve more from positive feedback than from negative feedback, with negative feedback even reducing performance for a non-trivial share of physicians. Experiments with laypersons replicate these results and show that struggles with negative feedback can be mitigated by giving incentives directly tied to improvement and by adding qualitative information that helps individuals interpret past performance. These results are consistent with behavioral models that suggest cognitive and emotional difficulties limit how well individuals use negative feedback. Thus, feedback interventions in healthcare should be carefully designed to mitigate counterproductive behavioral responses.

Results as a limerick

Are report cards a fad?

Or could they help just a tad?

We find feedback is tricky,

‘cuz priors are sticky

And the good helps more than the bad.

Rationing by Race (with Atheendar Venkataramani)

(Previously circulated under the title "Capacity Strain and Racial Disparities in Hospital Mortality ", NBER WP 30380)


As resources become more scarce, discrimination may lead to rationing on the basis of group identity rather than by more equitable mechanisms. We provide evidence of such consequential rationing on the basis of an individual's race in a high-stakes setting: healthcare. Using detailed, time-stamped data on over 100,000 patient admissions from a large health system in the United States, we show that in-hospital mortality increased for Black, but not White, patients as hospitals reached capacity (when biases in provider decision-making or healthcare protocols may emerge or be exacerbated). We identify rationing by wait times as a mechanism, and document a startling fact: sick Black patients waited longer for care than healthy White patients at all capacity levels. Finally, using novel text analysis techniques, we find suggestive evidence of racial disparities in provider attention and effort that worsen with increasing capacity strain.

Press: Tradeoffs Newsletter

Results as a limerick

On clinical capacity does care depend 

whether or not providers intend, 

Hospitals get busy,

all systems a-tizzy,

with disparities emerging in the end.