| rake {survey} | R Documentation |
Raking uses iterative post-stratification to match marginal distributions of a survey sample to known population margins.
rake(design, sample.margins, population.margins, control = list(maxit = 10, epsilon = 1, verbose=FALSE), compress=NULL)
design |
A survey object |
sample.margins |
list of formulas or data frames describing sample margins |
population.margins |
list of tables or data frames describing corresponding population margins |
control |
maxit controls the number of
iterations. Convergence is declared if the maximum change in a table
entry is less than epsilon. If epsilon<1 it is
taken to be a fraction of the total sampling weight. |
compress |
If design has replicate weights, attempt to
compress the new replicate weight matrix? When NULL, will
attempt to compress if the original weight matrix was compressed |
The sample.margins should be in a format suitable for postStratify.
Raking (aka iterative proportional fitting) is known to converge for any table without zeros, and for any table with zeros for which there is a joint distribution with the given margins and the same pattern of zeros. The `margins' need not be one-dimensional.
The algorithm works by repeated calls to postStratify
(iterative proportional fitting), which is efficient for large
multiway tables. For small tables calibrate will be
faster, and also allows raking to population totals for continuous
variables, and raking with bounded weights.
A raked survey design.
calibrate for other ways to use auxiliary information.
data(api)
dclus1 <- svydesign(id=~dnum, weights=~pw, data=apiclus1, fpc=~fpc)
rclus1 <- as.svrepdesign(dclus1)
svymean(~api00, rclus1)
svytotal(~enroll, rclus1)
## population marginal totals for each stratum
pop.types <- data.frame(stype=c("E","H","M"), Freq=c(4421,755,1018))
pop.schwide <- data.frame(sch.wide=c("No","Yes"), Freq=c(1072,5122))
rclus1r <- rake(rclus1, list(~stype,~sch.wide), list(pop.types, pop.schwide))
svymean(~api00, rclus1r)
svytotal(~enroll, rclus1r)
## marginal totals correspond to population
xtabs(~stype, apipop)
svytable(~stype, rclus1r, round=TRUE)
xtabs(~sch.wide, apipop)
svytable(~sch.wide, rclus1r, round=TRUE)
## joint totals don't correspond
xtabs(~stype+sch.wide, apipop)
svytable(~stype+sch.wide, rclus1r, round=TRUE)
## Do it for a design without replicate weights
dclus1r<-rake(dclus1, list(~stype,~sch.wide), list(pop.types, pop.schwide))
svymean(~api00, dclus1r)
svytotal(~enroll, dclus1r)
## compare to raking with calibrate()
dclus1gr<-calibrate(dclus1, ~stype+sch.wide, pop=c(6194, 755,1018,5122),
calfun="raking")
svymean(~stype+api00, dclus1r)
svymean(~stype+api00, dclus1gr)
## compare to joint post-stratification
## (only possible if joint population table is known)
##
pop.table <- xtabs(~stype+sch.wide,apipop)
rclus1ps <- postStratify(rclus1, ~stype+sch.wide, pop.table)
svytable(~stype+sch.wide, rclus1ps, round=TRUE)
svymean(~api00, rclus1ps)
svytotal(~enroll, rclus1ps)
## Example of raking with partial joint distributions
pop.imp<-data.frame(comp.imp=c("No","Yes"),Freq=c(1712,4482))
dclus1r2<-rake(dclus1, list(~stype+sch.wide, ~comp.imp),
list(pop.table, pop.imp))
svymean(~api00, dclus1r2)