Pool contrasts and comparisons from estimate_contrasts()

This function "pools" (i.e. combines) multiple estimate_contrasts objects, returned by estimate_contrasts(), in a similar fashion as mice::pool().

Usage

pool_contrasts(x, ...)

Arguments

x: A list of estimate_contrasts objects, as returned by estimate_contrasts().
...: Currently not used.

Value

A data frame with pooled comparisons or contrasts of predictions.

Details

Averaging of parameters follows Rubin's rules (Rubin, 1987, p. 76).

References

Rubin, D.B. (1987). Multiple Imputation for Nonresponse in Surveys. New York: John Wiley and Sons.

Examples

data("nhanes2", package = "mice")
imp <- mice::mice(nhanes2, printFlag = FALSE)
comparisons <- lapply(1:5, function(i) {
  m <- lm(bmi ~ age + hyp + chl, data = mice::complete(imp, action = i))
  estimate_contrasts(m, "age")
})
pool_contrasts(comparisons)
#> Marginal Contrasts Analysis
#> 
#> Level1 | Level2 | Difference |   SE |          95% CI |  t(1) |     p
#> ---------------------------------------------------------------------
#> 40-59  | 20-39  |      -4.56 | 2.20 | [ -9.15,  0.03] | -2.93 | 0.008
#> 60-99  | 20-39  |      -6.49 | 2.70 | [-12.12, -0.86] | -3.68 | 0.001
#> 60-99  | 40-59  |      -1.93 | 2.17 | [ -6.47,  2.60] | -1.29 | 0.212
#> 
#> Variable predicted: bmi
#> Predictors contrasted: age
#> Predictors averaged: hyp, chl (2e+02)
#> p-values are uncorrected.
#>