R: Add variables to a survey design

update.survey.design {survey} | R Documentation

## Add variables to a survey design

### Description

Update the data variables in a survey design, either with a formula for a new set of variables or with an expression for variables to be added.

### Usage

    ## S3 method for class 'survey.design'
    update(object, ...)
    ## S3 method for class 'twophase'
    update(object, ...)
    ## S3 method for class 'svyrep.design'
    update(object, ...)
    ## S3 method for class 'DBIsvydesign'
    update(object, ...)
    ## S3 method for class 'ODBCsvydesign'
    update(object, ...)

### Arguments

`object` | a survey design object
`...` | Arguments `tag=expr` add a new variable `tag` computed by evaluating `expr` in the survey data.

### Details

Database-backed objects may not have write access to the database and so `update` does not attempt to modify the database. The expressions are stored and are evaluated when the data is loaded.

If a set of new variables will be used extensively it may be more efficient to modify the database, either with SQL queries from the R interface or separately. One useful intermediate approach is to create a table with the new variables and a view that joins this table to the table of existing variables.

There is now a base-R function `transform` for adding new variables to a data frame, so I have added `transform` as a synonym for `update` for survey objects.

### Value

A survey design object

### See Also

`svydesign`, `svrepdesign`, `twophase`

### Examples

    data(api)
    dstrat<-svydesign(id=~1,strata=~stype, weights=~pw, data=apistrat,
    fpc=~fpc)
    dstrat<-update(dstrat, apidiff=api00-api99)
    svymean(~api99+api00+apidiff, dstrat)

[Package survey version 3.32-1 Index]