brrweights: Compute replicate weights

Description

Compute replicate weights from a survey design. These functions are usually called from as.svrepdesign rather than directly by the user.

Usage

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"))

Arguments

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.

Value

For brrweights a list with elements
weightstwo-column matrix indicating the weight for each half-stratum in one particular set of split samples
wstrataNew stratum variable incorporating merged or split strata
strataOriginal strata for distinct PSUs
psuDistinct PSUs
npairsDimension of Hadamard matrix used in BRR construction
samplerfunction returning replicate weights
For jk1weights and jknweights a data frame of replicate weights and the scale and rscale arguments to svrVar.

Details

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.

References

Levy and Lemeshow "Sampling of Populations". Wiley.