annual report 2011 - Office for Research - Northwestern University

Bernard Black
School of Law and Kellogg School of Management
Does Hospital Infection Reporting Affect
Actual Infection Rates?
Health-care associated infections (HAIs), often acquired in
hospitals, kill about 100,000 people annually. Many of these
infections are preventable. In response to the epidemic of
HAIs, many states have adopted laws requiring hospitals
to publicly report their infection rates. But whether public
reporting affects hospital behavior, and thus affects actual
infection rates, and by how much, is unknown.
Bernard Black, law instruction and finance, and coauthors
Hyun Kim and Myungho Paik of the University of Texas at
Austin have studied the first state (Pennsylvania) to require
detailed public reporting and one important type of highly
serious and often fatal infection, central-line-associated
bloodstream infections (known as CLABSI). Using a strong
difference-in-differences research design, they find that
a measure of CLABSI rates, based on hospital billing
records, drops by 23 percent in Pennsylvania relative to
states without public reporting. The drop in CLABSI rates
is concentrated in hospitals with high reported rates. This
suggests that public reporting in fact changes the behavior
of hospitals with high infection rates.
They also compare their nonreported measure with the
CLABSI rates that hospitals publicly report. The publicly
reported rates drop far faster, by 40 percent over 2005–07;
more than twice the 17 percent drop in inpatient rates
during this period. This suggests that hospitals are “gaming”
the publicly reported rates. That is, some of the decline
in reported rates appears to be real, but some appears to
reflect hospitals changing how they report infections.
30 Annual Report 2011 | Excellence in Research
Black and his coauthors recently received a $450,000 grant
from the Robert Wood Johnson Foundation to extend this
Courtesy of B. Black
research to other states and other types of HAIs.
The figure below presents key results. The top blue line
shows CLABSI rates in nonreporting states; the red line
shows rates in Pennsylvania. The two lines are parallel
prior to the beginning of public reporting in Pennsylvania
but diverge afterward. The green dotted line shows the
Pennsylvania publicly reported rates for the available period
of 2005–07, extrapolated before and after this period based
on rates estimated from billing records. The rapid drop in
the green line during 2005–07 suggests that hospitals are, in
part, gaming the public reports.