Capsule Commentary on Silvestri et al., Impact of Cost Display
on Ordering Patterns for Hospital Laboratory and Imaging Services
Joseph A. Ladapo, MD, PhD
David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
J Gen Intern Med
© Society of General Internal Medicine 2018
ilvestri et al. evaluated an economics-based intervention
that is relatively innovative in healthcare but would be
considered commonsense in other fields—namely, providing
buyers (physicians) with information about costs of the ser-
vices they purchase.
Using a pre-post design, they found that
displaying costs in the EHR for lab and imaging tests was
associated with a decrease in the number of studies ordered for
hospitalized patients and a decrease in overall lab and imaging
Inferences about causal relationships in non-randomized
studies are fraught with risks. However, initiation of the inter-
vention was associated with a sharp step-off in cost trends, so I
am persuaded to believe that it causally influenced physician
decision-making. While the effects were quantitatively mod-
est, they are substantial at the hospital or health system level,
assuming no untoward health effects of decreased testing.
Altogether, these are important findings.
But what appears to Bonly^ be a study about cost
display is really something much more. The authors’ study
introduces a trove of scientific areas of inquiry that have
intrigued economists and psychologists alike. The pur-
chase of services by physicians on behalf of patients is
really a classic principal-agent problem in economics.
providing care, physicians act as agents for their patients,
the principals. Implied in the results of Silvestri et al. is
that physicians, when presented with cost information,
increasingly concluded that the marginal cost of a lab or
imaging test exceeded its marginal benefit. But how well
do physicians know the preferences of their patients?
Would a well-informed patient feel similarly to his or
her physician about the cost-benefit balance of a test or
study? Another interesting issue relates to the decision
psychology of interpreting prices. For example, physicians
another test that is more expensive,
and we are all famil-
iar with the purchase-inducing effects of ending prices
with the number 9, compared to other numbers.
should recognize that the study by Silvestri et al. serves
as a bridge to areas of investigation at the heart of physi-
cian decision-making and the patient-doctor relationship.
Corresponding Author: Joseph A. Ladapo, MD, PhD; David Geffen
School of Medicine at UCLA, Los Angeles, CA, USA
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