preselect_vars: Extract variable names from mf_preselect object

In metaforest: Exploring Heterogeneity in Meta-Analysis using Random Forests

Description

Returns a vector of variable names from an mf_preselect object, based on a cutoff criterion provided.

Usage

preselect_vars(x, cutoff = NULL, criterion = NULL)

Arguments

x	Object of class mf_preselect.
cutoff	Numeric. Must be a value between 0 and 1. By default, uses .95 for bootstrapped preselection, and .1 for recursive preselection.
criterion	Character. Which criterion to use. See Details for more information. By default, uses 'ci' (confidence interval) for bootstrapped preselection, and 'p' (proportion) for recursive preselection.

Details

For criterion = 'p', the function evaluates the proportion of replications in which a variable achieved a positive (>0) variable importance. For criterion = 'ci', the function evaluates whether the lower bound of a confidence interval of a variable's importance across replications exceeds zero. The width of the confidence interval is determined by cutoff.

For recursive preselection, any variable not included in a final model is assigned zero importance.

Value

Character vector.

Examples

## Not run: 
data <- get(data(dat.bourassa1996))
data <- escalc(measure = "OR", ai = lh.le, bi = lh.re, ci = rh.le, di= rh.re,
               data = data, add = 1/2, to = "all")
data$mage[is.na(data$mage)] <- median(data$mage, na.rm = TRUE)
data[c(5:8)] <- lapply(data[c(5:8)], factor)
data$yi <- as.numeric(data$yi)
preselected <- preselect(formula = yi~ selection + investigator + hand_assess + eye_assess +
                        mage +sex,
          data, study = "sample",
          whichweights = "unif", num.trees = 300,
          replications = 10,
          algorithm = "bootstrap")
preselect_vars(preselected)

## End(Not run)

metaforest documentation built on Jan. 8, 2020, 9:06 a.m.