Sustaining Informal Caregivers - New York State Office for the Aging

Appendix E
Sample Weighting Scheme 8
The survey employed a multiple-stage sample design. In stage one, Area Agencies on Aging
(AAAs) were grouped into three strata: urban, rural and suburban strata. Then a sample of 50%
of AAAs was selected in the second stage. In stage three, a sample of caregivers within each
sampled AAA were randomly selected.
Weighting of each caregiver was computed by taking the inverse of the selection probability for
each sampled caregivers and adjusted for non-response. It was done in two steps: calculation of
base weights and non-response adjustment.
Base Weights
The base weight is the inverse of the overall selection probability of a caregiver. The base weight
of a caregiver can be obtained by calculating the base weight of an AAA and multiplying that
weight by the within-AAA-level base weight of a caregiver in the caregiver support program
within that AAA.
The base weight of an AAA i can be expressed as
M i
a i = =
P m
1
i
i
and the base weight of a caregiver in a caregiver support program within an AAA can be
Nij
expressed as v ij = =
Pij
nij
1
The basic weight can be expressed as
If
w ij = a i × vij
Non-response Adjustment
r
n ij denotes the number of caregivers that responded to the survey, then the non-response
adjustment was calculated as follows:
N r ij
v ij == r
nij
Final Weight
The overall adjusted weight of a caregiver within AAA
W = w × v
ij
ij
r
ij
i
can be expressed as:
8
This scheme is developed based on the technical documentation of the third Administration on Aging’s National
Survey.
40