brrweights {survey} | R Documentation |
Compute replicate weights from a survey design. These functions are
usually called from as.svrepdesign
rather than directly
by the user.
brrweights(strata, psu, match = NULL, small = c("fail", "split", "merge"), large = c("split", "merge", "fail")) jk1weights(psu,fpc=NULL, fpctype=c("population","fraction","correction")) jknweights(strata,psu, fpc=NULL, fpctype=c("population","fraction","correction"))
strata |
Stratum identifiers |
psu |
PSU (cluster) identifier |
match |
Optional variable to use in matching. |
small |
How to handle strata with only one PSU |
large |
How to handle strata with more than two PSUs |
fpc |
Optional population (stratum) size or finite population correction |
fpctype |
How fpc is coded. |
JK1 and JKn are jackknife schemes for unstratified and stratified
designs respectively. The finite population correction may be
specified as a single number, a vector with one entry per stratum, or
a vector with one entry per observation (constant within strata).
When fpc
is a vector with one entry per stratum it may not have
names that differ from the stratum identifiers (it may have no names,
in which case it must be in the same order as
unique(strata)
). To specify population stratum sizes use
fpctype="population"
, to specify sampling fractions use
fpctype="fraction"
and to specify the correction directly use
fpctype="correction"
In BRR variance estimation each stratum is split in two to give half-samples. Balanced replicated weights are needed, where observations in two different strata end up in the same half stratum as often as in different half-strata.BRR, strictly speaking, is defined only when each stratum has exactly two PSUs. A stratum with one PSU can be merged with another such stratum, or can be split to appear in both half samples with half weight. The latter approach is appropriate for a PSU that was deterministically sampled.
A stratum with more than two PSUs can be split into multiple smaller strata each with two PSUs or the PSUs can be merged to give two superclusters within the stratum.
When merging small strata or grouping PSUs in large strata the
match
variable is used to sort PSUs before merging, to give
approximate matching on this variable.
For brrweights
a list with elements
weights |
two-column matrix indicating the weight for each half-stratum in one particular set of split samples |
wstrata |
New stratum variable incorporating merged or split strata |
strata |
Original strata for distinct PSUs |
psu |
Distinct PSUs |
npairs |
Dimension of Hadamard matrix used in BRR construction |
sampler |
function returning replicate weights |
For jk1weights
and jknweights
a data frame of replicate
weights and the scale
and rscale
arguments to svrVar
.
Levy and Lemeshow "Sampling of Populations". Wiley.
hadamard
, as.svrepdesign
,
svrVar