1.
Study of uptake and retention.
The PROPOSAL,
while not entirely in accord with
epidemiologic methodology,
standard
is I think well adjusted to the
actual conditions in which the field work must be done.
I favor building upon the plan.
would recommend,
complete,
Hence
The principal addition I
as a preliminary,
is the development of a
stratified sampling frame before field work starts.
This sampling frame,
or list,
of the affected population will
systematize all existing information about such factors as
age,
sex,
exposure.
location
of
occupation
and
potential
One advantage in this particular case is that this
listing can make
full
(ground area survey,
mination,
residence,
together
use of
the other elements of
study
animal sampling and particle-size deter-
with
the
earlier work
in
these
three
areas).
The function of such a sampling frame is to provide the
necessary basis for design and implementation of an optimal
stratified random sample for accurate determination of uptake
and retention.
The intent is to follow the main outline of
the PROPOSAL requiring annual measurement of levels in small
samples of approximately six subgroups of the population:
once the frame is complete,
any statistician on our collabo-
rator's staff could design this sample readily.
samples would not turn out exactly 10,
while still satisfying objectives.
Subgroup
but can be kept
small
The most difficult element
here is sampling randomly in the field:
but this is worth
insisting upon because of the scientific value of determinations made in this way.
QS 53009 830