APPENDIX A
Methods of Computation
The computations underlying the factors given in tables 90-93 are basedon the accumulation of one patient per day for 30 days, then decumulationover time to zero. The remaining and disposition distributions are shownin tables C-1 and C-2 and provide the probabilities for patients remainingin hospital at specified points in time (Ri) as well as theprobability of either return to duty or death, respectively (Gi),or of experiencing a disability separation (Di), each as a functionof time. The evacuee factors are given in tables C-3 and C-4 and providethe probability of evacuation by the end of each indicated day. The variousaccumulation-decumulation and disposition factors may be computed as follows:
Patients Remaining in Theater
To estimate the number of patients remaining in theater, under the assumptionof one theater admission per day through the first period of estimate-thennone, the following are defined:
d= number of days in the period of estimate,
di= last day of the ith period of estimate, that, is,di=i×d,
p= number of days in the theater evacuation policy, and note that the policyconsiders a, patient's total hospital time in theater,
Ri= probability that a patient's total hospitalization anywherewill exceed i days (see tables C-1 and C-2),
Di= probability that a patient will be separated for disabilityby the end of the ith day (see tables C-1 and C-2)
Ei,p= probability that, a patient will be evacuated by the endof the ith day under evacuation policy p (see tables C-3 and C-4),and note that Ep,p which insures that all disability separationswill occur in CONUS.
ROi= number of patients remaining in overseas hospitals at theend of day i under the assumption of one theater admission per day throughthe first period of estimate (d1)-then none.
Thus, when p<d
(1)
and, ROdj=0 for j=2, 3, 4, ...
When p>d or p=d, and defining d0=0,
(2)
for all j where dj<p or dj=p, and ROdj=0for all j where dj>p.
Patients remaining in CONUS
To estimate the number of patients remaining in CONUS hospitals at theend of day i, under the assumption of one theater admission per day throughthe first period of estimate- then none.
When p<d,
(3)
and,
(4)
for j=2, 3, 4, ...
When p>d or p=d,
(5)
for all j where dj<p,
and, as in (4) above for all j where dj>p or dj=p.
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Patients Evacuated From One Echelon to Another
To estimate patient evacuees between any two echelon system (Army-COMMZ,Theater-CONUS), where AEj is the number of evacuees during the jthperiod of estimate, under the assumption of one admission per day throughthe first period of estimate- then none. Note that the last patient evacuatedmust occur by the end of day d+p-1.
When p<d,
(6)
(7)
