BOOKS OF RtfiDIfGS - PAHO/WHO

- 229 -
METHODS
Parameters Affecting Hospital Occupancy
and Implications for Facility Sizing
By Walton M. Hancock, David B. Magerlein, Robert H. Siorer, and
lames B. Martin
Simulation is used to investigate the effects on hospital occupancy of the
number of beds in the facility, the percentage of patients who are emergencies,
the percentage of elective patienta who are acheduled, and the average
lengths of stay of emergency and elective patients. A practical method is
presented for estimating the optimum suze of a short-term hospital on the
basis of expected demand, and use of the resulta in planning is discussed.
To operate at minimum cost it is imperative that a hospital not
contain more beds than necessary to meet demand. The nontrivial
costs of building, stafflag, and maintaining unused beds are unnecessary
and are ultimately bdrne by the health care consumer. The variable
cost of staffing and maintaining a hospital bed was found to be
$10,130 per year in one study [1] and $16,201 per year in another [2],
and the fixed cost of building a bed has been quoted as $50,000 [3].
Thus, considerable savings are possible by eliminating beds in an
overbedded Hospital (saving variable costs) and by preventing the construction
of unneeded beds (saving both fixed and variable costs).
A simulation-based analysis of the effects of several parameters
on hospital occupancy is presented. The parameters investigated are
number of beds in the facility, percentage of patients who are emergencies,
percentage of elective patients whose admission date is set in
advance (scheduled patients), and mean lengths of stay of emergency
and elective patients. A practical method is developed for predicting
the correct size of hospital facilities, given the expected demand. Current
planning methods such as the Hill-Burton formula, the Poisson
assumption, and that of Shonick [4] are shown to be inappropriate
ThiJ study was supported by PHS grant no. HS00228 from ¿he National Center
for HIalth Services Rescarch (DHEW) and by the W.K. Kellogg Foundation
through the Greater Detroit Arca Hospital Council, Inc.
Addrdeu communications and requests for reprints to Walton M. Hancock,
HEALTH ProCessor of Induswlrial and Operations Engineering and Hospital Administration,
SERVICES Program and Bureau of Hospital Administration, University oJ Michigan School of
RESEARCH Public Health, 1420 Washington Heights, Ann Arbor, MI 48109. David P. Mager.
ARC. A'I cin is a graduate student and Robert H. Storr is an undergraduate student, both
in industrial and operations engineering; and ]ames B. Martin is assistant professor
of hospital adminisuration. All of the authors are at the University of Michigan.
0017-9124/78/03027614/$02.00/0
( 1978 Hospital Research and Educational Trust