c - usaid

34
would not be fulfi lLed. We can tarm this as another
consistency condition.
The simplest formula that fuL fiLs the above-mentioned
requirements is
uf t
ui [t) = u 0) ..... (4.12)
u[O]
which increases such u (0) in the same proportion. In the
u {1o)
averaging process, the ratio -----
u(0)
achieved.
becomes one, and consistency is
But it should be noted that the values obtained in this
way ore not to be considered as unique,
because formula [4.12) is
on Ly one of the ony possible formulas that can be thought of, as
we shall see Later.
The , (t) values obtained by formula [4. 12] can be xpected
to be consistent with the TFR target because uft] was derived
from TFR. Dut wE, hove .to check what the corresponding CBR is.
For this purpose, w e use the following formulas:-
N i t= HWA 1 (t [1-s i t).u 1 (t).e (tJ]C (t]
i ai
.[ )t N. (t).ASNFR i t)
1 *1 i
1000
CBR(t) = -- T B(t]
P~t]
Let us assume,
for purposes of avoiding unwarranted optimism, that
the C BR obtained in this way is found to be different from what
has been specified as a target. In that case, either the CBRtarget
or the TFR target needs to ba revised, or, if that raises
other di fficultijs, a way should be found to re-adjust formula
(4.12].
Th or.oticaLly, what we nod is a formula which contains a
n
trend regulator whose values can be adjusted so as to be
consistent not onLy with a TFR target but also with a CBR target.