The impact of information disclosure
on quality of care in HMO markets
Department of Health Policy and Administration, The Pennsylvania State University, 601H Ford Building, University Park, PA 16802, USA
Address reprint requests to: Kyoungrae Jung, Department of Health Policy and Administration, The Pennsylvania State University, 601H
Ford Building, University Park, PA 16802, USA. Tel: þ1-814-863-8129; Fax: þ1-814-863-2905; E-mail: email@example.com
Accepted for publication 19 September 2010
Objective. To examine the impact of voluntary information disclosure on quality of care in Health Maintenance Organization
(HMO) markets in the USA.
Setting. Commercial HMOs that collected a set of standardized quality meausres, Health Plan Employer Data and
Information Set (HEDIS), between 1997 and 2000 in the USA (1062 HMO-years). After collecting the HEDIS data, some
HMOs disclosed their HEDIS-quality scores to the public (disclosing HMOs), whereas some HMOs declined to disclose the
information (non-disclosing HMOs).
Design. A secondary data analysis based on 4 years of quality scores of HMOs. The study uses non-disclosing plans as a
control group. A treatment-effects model is used to address a potential bias associated with voluntary disclosure decisions by
Main Outcome Measure(s). The study focuses on 13 HEDIS clinical indicators. On the basis of these indicators, a plan-
level composite score and four domain scores were constructed. The four domains are childhood immunizations, treat-
ments/exams for chronic conditions, screening tests and maternity services.
Results. Public disclosure leads to an increase of 0.72 composite score units, which corresponds to ?7% points in original
quality scale (0–100%). The degree of quality improvement differed by the type of services.
Conclusions. Public release of quality information had a significant and positive effect on quality in HMO markets during
the earlier years of the voluntary disclosure program; however, the improvement was not universal across all quality measures.
Keywords: quality information, public disclosure, quality of care, HMO markets
Public reporting of quality information is a growing move-
ment in the current US healthcare system. Almost every state
has quality reporting programs for hospitals, and the Center
for Medicare and Medicaid Services (CMS) has initiated
public disclosure programs for hospitals, managed care
plans, nursing homes and home health agencies. Information
disclosure also has received attention in other countries. For
example, in South Korea, a national insurance review agency
has been publicly releasing the information about antibiotics
use rates among healthcare organizations since 2006 .
Several countries have attempted to develop and collect
quality measures capturing consumer experience with health-
care systems .
The rationale behind information disclosure is compelling.
Economic theory suggests that if consumers cannot observe
quality of services, providers will not have an incentive to
improve quality . Thus, it is expected that publicly
releasing relevant information will help consumers recognize
differences in quality among individual providers, which will
in turn motivate providers to improve quality. Some also
suggest that public reporting may directly influence health-
care providers to change their practice because it serves as a
mechanism to provide feedback on their practice: if providers
are informed about competitors’ quality scores, they may be
motivated to improve quality . With these expectations,
information disclosure has been adopted in varied healthcare
As public reporting rapidly expands, several studies have
examined the effects of information disclosure on quality in
hospital or nursing home markets but produced mixed
results [5–9]. In Health Maintenance Organization (HMO)
markets, some studies reported improvements in HMOs’
quality scores following nation-wide public disclosure pro-
grams [10, 11]. However, because none of these studies used
control groups, the reported improvement in HMO quality
cannot be fully attributed to public disclosure initiatives.
International Journal for Quality in Health Care vol. 22 no. 6
# The Author 2010. Published by Oxford University Press in association with the International Society for Quality in Health Care;
all rights reserved461
International Journal for Quality in Health Care 2010; Volume 22, Number 6: pp. 461–468
Advance Access Publication: 12 October 2010
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