pf_sv_test | R Documentation |
Use the test proposed in Pfeffermann and Sverchkov (1999) to check whether a regression model is specified correctly without weights.
pf_sv_test(
model,
data = NULL,
weights,
sims = 1000,
digits = getOption("jtools-digits", default = 3)
)
model |
The fitted model, without weights |
data |
The data frame with the data fed to the fitted model and the weights |
weights |
The name of the weights column in |
sims |
The number of bootstrap simulations to use in estimating the variance of the residual correlation. Default is 1000, but for publications or when computing power/time is sufficient, a higher number is better. |
digits |
An integer specifying the number of digits past the decimal to
report in the output. Default is 3. You can change the default number of
digits for all jtools functions with
|
This is a test described by Pfeffermann and Sverchkov (1999) that is designed to help analysts decide whether they need to use sample weights in their regressions to avoid biased parameter estimation.
It first checks the correlation of the residuals of the model with the weights. It then uses bootstrapping to estimate the variance of the correlation, ending with a t-test of whether the correlation differs from zero. This is done for the squared residuals and cubed residuals as well. If anyone of them are statistically significant (at whatever level you feel appropriate), it is best to do a weighted regression. Note that in large samples, a very small correlation may have a low p-value without a large bias in the unweighted regression.
Pfeffermann, D., & Sverchkov, M. (1999). Parametric and semi-parametric estimation of regression models fitted to survey data. Sankhya: The Indian Journal of Statistics, 61. 166-186.
Other survey tools:
svycor()
,
svysd()
,
weights_tests()
,
wgttest()
# Note: This is a contrived example to show how the function works,
# not a case with actual sammpling weights from a survey vendor
if (requireNamespace("boot")) {
states <- as.data.frame(state.x77)
set.seed(100)
states$wts <- runif(50, 0, 3)
fit <- lm(Murder ~ Illiteracy + Frost, data = states)
pf_sv_test(model = fit, data = states, weights = wts, sims = 100)
}
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.