BOOKS OF RtfiDIfGS - PAHO/WHO

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Regional Heolth-Services Planning 635
requiren:mitas, a in e.:haaliasm for exanliniing tlic' in:renmental gaitis to be expected fro)m
adding ad(litio(:: l e(enter,. alid a ii'i:1s to e)xplore th(
tívc cntriteria upn solutions.
it(ierentia:l (ffetets of alterna-
Suppose thatl the hcalth planner can) select a criterion, atnd wishis to determine
the optimal loc1ationri of G primiary caree ciitters. wliere O· cea:u r:tg. frLrom on, upa to
some maximum fiasible ¡number. (If somne trieuters :air(,ady exist iti thc region, lle
may want to hiolhd these illociations constant anil conisider only the optimal locationis
of additiot.id centers.) By using the model, lie eaní compare the expected incremental
gaiiis in thie c-riterion valuti for ea:h ah:itiotiual center. If tlie lhoicje :umong
sevcral olthjttives is unia::tr, lihe prorlss of allor:nting Celiters can l)e relp.:ated to
maximize eacll objective. for vach value of G. This facilita:tes a compari4on of
different locations in terms of their relative erfec:ts on muiltiple objectivec.
Suchla :a us( of thi( mod(el is illustr:at(d by 1lW( h xa tinl)el it thie followiltg ;se(liot.
The ,i))ln'ai':atl restilts iar. o|r t:'hi):l for a conill)letc, ont-lille, ilnl era:ctive, FUILTUAN IV
version of the mode-l, programmein to be suitable for several hundred census blockli4,
and up to 20 centers and 8 substrata. The program determines the values for all
TAISI.u.: 1
UTiI.i.%iTioN C'iA.ll.\ ¢'TIr:tlIl'-T.^ 1O:A\II STIIA.\rUM
Utilization rate at immediate proximity
|litgh Low
BIarrier effect
tanee
f dis-. Stl. ratum l j
v, -5.2
I¡ .Slratium j-4
& ¿=l1.9
d -. O.0005 d4-0.0008
lligh Sratrtitmjj=3 St rat tiau j -2
; =eli.2 t a2 .1
: · ,Z,,o d.i lai
115
four criteria described above although only oune is optimized at a tinme. wse of the
model provides understanding of the problem and insights into the impact of various
cnrteria on the solution in a hypothetical example.
AN EXA.IPLE
AMsuYE TIIAT health care centera are to be located withii the regiom d.,cribed itn Fig. 1.
The regiotl has 4 strata, with vi and di a.s given itn Tanhble 1. Strata 1 and 3 have manrkedly
higher utilizatiotn rates al imtme