BOOKS OF RtfiDIfGS - PAHO/WHO

- 268 -
A Spatial-Allocation Model bfor Regional
Health-Services Planning
,Villiam J. AL-:rnathy and John C. llertshey
Stanford Unwersi*y, Staniord, California
(letccivc~l A\utgust 12, 1'971)
In planning for health services, the need arises to determine the location,
capacity. and number of health centers for a geographically defined region.
The present paper formulates this problem in a form convenient for solution
and presents results from the model to clarify some important aspects of this
allocation decision. The planning region is assumed to consist of geographically
defined subareas or census blocks, of known location. The population is
stratified in such a way that each stratum exhibits relatively homogeneous
patteras of health-care utilization. The model characterizes the effects of
center locations upon aggregate utilization and utilization of individual centers,
sad gives optimal locations of centers with respect to several alternative criteru.
An example illustrating computational feasibility and the implications
of various criteria for the location decision is presented.
HE PROBLENl, OF' determining ipatial locatioxns of primary health-care :enters
for a dispersed population is an important issue in primary health-care planning.
This paper forniulates the problem iii terms oi four different criteria. 'The importance
of accepting census statistics as .source data is recognized in the formulation
·and in the choice of optimization procedure.
The distance from individuals in a community to sources of care is a recognized
' ' t
barrier to utilization." "1 Several types of decay functions have been proposed
to describe the inverse relation between distance to medical facilities and utilization
·M these facilities.l " '"- Recent research by the authors analyzes choice behavior
among facilities when several facilities at varying distances are available. z'l
It ¡e
demonstrated that the influencc of distance upon choice behavior iN much stronger
tairn ik the influence of distaince ulpn overall utilization.
In addition, it is well known that demographic, socioeconomic, and health-
*-tatus factors all influence individuals' medical-facility utilization. Strata that are
?differentiated by these factors show different utilization patterns as a funetion of
distane .12.'," That ,''I , is, distancc is a larger barrier to utilization for ~some
strata than for others. Substantial progress has been mnade in understanding the
e oomplex interactions of distance and socioeconomic variables. However, a method
for using these interactions to suggest alternativc locations of medical facilities has
not heretofore been developed.
A frequently stated goal of regional primary-ihealth-care planners i¡ to allocate
facilitie to locations in sueih a manner os to provide as much of the primary care
Idemanded by the population as possible. Y'et this may conflict with other goals.
For example, if the health planner maximizet total utilization, centers may be
' placed closer to areas that contain large numbers of people for whom distance is a