pram_strata: Post Randomization

Description

To be used on categorical data. It randomly change the values of variables on selected records (usually the risky ones) according to an invariant probability transition matrix.

Usage

pram_strata(obj, variables=NULL,strata_variables=NULL,
        weights=NULL, pd=0.8, alpha=0.5)
## S3 method for class 'pram_strata':
print(x, ...)

Arguments

obj

Input data or object of class sdcMicroObj

variables

Names of variables for Post Randomization

strata_variables

Names of variables for stratification (will be set automatically for an object of class 'sdcMicroObj'

weights

a weight for each variable

Output of pram_strata

...

further input

minimum diagonal entries for the generated transition matrix P. Either a vector of length 1 or a vector of length ( number of categories ).

alpha

amount of perturbation for the invariant Pram method

Value

a modified sdcMicroObj object or new variables with the suffix "_pram" will be created.

References

http://www.gnu.org/software/glpk http://www.ccsr.ac.uk/sars/guide/2001/pram.pdf

Examples

Run this code

data(testdata)
res <- pram_strata(testdata,
  variables="roof",strata_variables=c("urbrur","sex"))
print.pram_strata(res)
res1 <- pram_strata(testdata,variables=c("roof","walls","water"),
  strata_variables=c("urbrur","sex"))
print.pram_strata(res1)
res2 <- pram_strata(testdata,variables=c("roof","walls","water"),
  strata_variables=NULL)
print.pram_strata(res2)

## for objects of class sdcMicro:
data(testdata2)
sdc <- createSdcObj(testdata2,
  keyVars=c('urbrur','roof','walls','water','electcon','relat','sex'), 
  numVars=c('expend','income','savings'), w='sampling_weight')
sdc <- pram_strata(sdc, variables=c("urbrur"))