Effect of Part-time Practice on Patient Outcomes
Patricia H. Parkerton, PhD, MPH, Edward H. Wagner, MD, MPH,
Dean G. Smith, PhD, Hugh L. Straley, MD
BACKGROUND: Primary care physicians are spending fewer
hours in direct patient care, yet it is not known whether
reduced hours are associated with differences in patient
OBJECTIVE: To determine whether patient outcomes vary
with physicians' clinic hours.
DESIGN: Cross-sectional retrospective design assessing pri-
mary care practices in 1998.
SETTING: All 25 outpatient-clinics of a single medical group in
PARTICIPANTS: One hundred ninety-four family practitioners
and general internists, 80% of whom were part-time, who
provided ambulatory primary care services to specified HMO
patient panels. Physician appointment hours ranged from 10
to 35 per week (30% to 100% of full time).
MEASUREMENTS: Twenty-three measures of individual pri-
mary care physician performance collected in an administra-
tive database were aggregated into 4 outcome measures:
cancer screening, diabetic management, patient satisfaction,
and ambulatory costs. Multivariate regression on each of the 4
outcomes controlled for characteristics of physicians (admin-
istrative role, gender, seniority) and patient panels (size, case
mix, age, gender).
MAIN RESULTS: While the effects were small, part-time
physicians had significantly higher rates for cancer screening
(4% higher, P = .001), diabetic management (3% higher,
P = .033), and for patient satisfaction (3% higher, P = .035).
After controlling for potential confounders, there was no
significant association with patient satisfaction (P = .212) or
ambulatory costs (P = .323).
CONCLUSIONS: Primary care physicians working fewer clinical
hours were associated with higher quality performance than
were physicians working longer hours, but with patient
satisfaction and ambulatory costs similar to those of physi-
cians working longer hours. The trend toward part-time
clinical practice by primary care physicians may occur without
harm to patient outcomes.
KEY WORDS: part-time physicians; quality of care; primary
care; physician characteristics; patient satisfaction.
J GEN INTERN MED 2003;18:717±724.
hile physicians' total hours of work have not
the time that primary care physicians
spend in direct patient care decreased by 10% during the
In part, this decrease in clinical hours was
associated with the new and varied practice environments.
As integrated delivery systems, managed care organiza-
tions, and other health services organizations have adapted
to and innovated practices, the employment of part-time
physicians has increased (T. Syltebo, MD, in conversation,
January 2000). Whether the reduction in hours is dictated
by organizations, is a consequence of organizational
changes, or is a personal choice of physicians, the impact
of part-time practice on patient outcomes is unknown.
Physicians reduce their clinical time for a wide variety
Some physicians hold related responsibilities
within the same environment, such as teaching, conduct-
ing research, or managing programs on a part-time basis.
Others choose to care for family members, foster social
causes, pursue avocations, begin entrepreneurial enter-
prises, or extend their education (interviews conducted by
Parkerton in 1999). Furthermore, the primary care role
has been changed by the increased specialization of phy-
sicians, including the emergence of hospitalists, and the
administrative demands (and opportunities) of managed
The trend toward more primary care physicians
engaging in clinical practice on a part-time basis gives rise
to concerns about patient outcomes, deterring some
managed care organizations from employment of part-time
Because primary care is defined as continuous,
coordinated, and comprehensive care,
it could easily be
inferred that continuous physician availability is important
and that a traditional, full-time work schedule would be
beneficial to patient care. However, validation that physi-
cians' clinic hours are a marker for better patient care is
unavailable. In one academic setting, for example, part-
time physicians' performance did not differ from that of
To shed more light on this line of
inquiry, we attempted to understand the consequences
of reduced hours in the community ambulatory setting,
and investigated the association between clinical hours and
patient outcomes. While previous studies have assessed
they have neither enumerated
nor evaluated direct patient-care hours as a continuous
This study examines the association
between the number of physician primary care clinical hours
Received from the Department of Health Services, University of
California at Los Angeles (PHP), Los Angeles, Calif; the
University of Washington and Sandy MacColl Institute for
Healthcare Innovation (EHW), Seattle, Wash; the Department
of Health Management and Policy, University of Michigan (DGS),
Ann Arbor, Mich; and Permanente Medical Group and Group
Health Cooperative of Puget Sound (HLS), Seattle, Wash.
Address correspondence and requests for reprints to Dr.
Parkerton: Department of Health Services, UCLA School of Public
Health, Box 91772, Los Angeles, CA 90095-1772 (e-mail: