Calibrating 2016 ANES data by linear regression.

The following makes use of the survey package. You may need to install it from CRAN using the code install.packages("survey") if you want to run this on your computer. (The package is already installed on the notebook container, however.)

library(survey)

Loading required package: grid
Loading required package: Matrix
Loading required package: survival

Attaching package: 'survey'

The following object is masked from 'package:graphics':

    dotchart

The following loads data created in an earlier example.

load("anes-2016-vprevote-design.RData")

calibrate expects the names of the calibration vectors to be like those of regression coefficents.

cal_names(~recall12+vote16,anes_2016_vprevote_desgn)

[1] "(Intercept)"     "recall12Romney"  "recall12Other"   "recall12No vote"
[5] "vote16Trump"     "vote16Other"     "vote16No vote"

The following code defines a function creates a vector suitable for calibration from the data frames that postStratify() or rake() use

calib_counts <- function(formula,frames){
    dframe2coef <- function(data){
        fname <- names(data)[1]
        flevels <- as.character(data[[1]])
        Freq <- data$Freq
        coefs <- c(sum(Freq),Freq[-1])
        names(coefs) <- c("(Intercept)",
                          paste0(fname,flevels[-1]))
        coefs
    }
    vars <- all.vars(formula)
    for(i in seq_along(vars)){
        var_i <- vars[i]
        frame_i <- frames[[var_i]]
        coef_i <- dframe2coef(frame_i)
        if(i==1)
            res <- coef_i
        else
            res <- c(res,coef_i[-1])
    }
    res
}

We now apply this function to get the calibration criteria. The file “popl-results.RData” contains the population-level ata.

load("popl-results.RData")
calib_anes16 <- calib_counts(~recall12+vote16,
                             list(recall12=pop.recall12,
                                  vote16=pop.vote16))

Finally we calibrate the ANES sample.

anes_2016_prevote_desgn_calib <- calibrate(
    anes_2016_vprevote_desgn,~recall12+vote16,
    population=calib_anes16)

100*svymean(~recall12,design=anes_2016_prevote_desgn_calib)

                    mean SE
recall12Obama   28.01970  0
recall12Romney  25.90182  0
recall12Other    0.95053  0
recall12No vote 45.12795  0

100*svymean(~vote16,design=anes_2016_prevote_desgn_calib)

                 mean SE
vote16Clinton 26.3355  0
vote16Trump   25.1883  0
vote16Other    3.1324  0
vote16No vote 45.3439  0

save(anes_2016_prevote_desgn_calib,file="anes-2016-prevote-desgn-calib.RData")