There are three types of replicate weight that can be created with as.svrepdesign.
Jackknife (JK1 and JKn) weights omit one PSU at a time. Balanced
repeated replicates (BRR and Fay) omit or downweight half the
sample. Bootstrap replicates resample PSUs from an estimated
population.
All these types of weights are created by `as.svrepdesign`,
according to the `type` argument. The default is JK1 weights for
an unstratified sample and JKn for a stratified sample.

data(api) dclus1<-svydesign(id=~dnum, weights=~pw, data=apiclus1, fpc=~fpc)Converting this design to use unstratified jackknife (JK1) weights is as simple as

rclus1<-as.svrepdesign(dclus1)To convert to bootstrap weights, specify the

bclus1 <- as.svrepdesign(dclus1,type="bootstrap", replicates=100)Balanced Repeated Replicates are designed for surveys with two PSUs in each stratum (although

data(scd) scdnofpc<-svydesign(data=scd, prob=~1, id=~ambulance, strata=~ESA, nest=TRUE)To convert to use BRR weights, we specify

scd2brr <- as.svrepdesign(scdnofpc, type="BRR")Fay's method is a modified version of BRR that uses weights of 2-ρ and ρ rather than 2 and 0 for PSUs in and not in a particular half-sample.

scd2fay <- as.svrepdesign(scdnofpc, type="Fay",fay.rho=0.3)

Thomas Lumley Last modified: Tue Apr 12 12:54:05 PDT 2005