strata_match {stratamatch}

Strata Match

Description

Match within strata in series using optmatch. Note that this function requires that the R package optmatch is installed.

Usage

strata_match(object, model = NULL, method = "prop", k = 1)

Arguments

object

a strata object

model

(optional) formula for matching. If left blank, all columns of the analysis set in object will be used as covariates in the propensity model or mahalanobis match (except outcome, treatment and stratum)

method

either "prop" for propensity score matching based on a glm fit with model model, or "mahal" for mahalanobis distance matching by the covariates in model.

k

the number of control individuals to be matched to each treated individual. If "k = full" is used, fullmatching is done instead of pairmatching

Value

a named factor with matching assignments

See Also

https://cran.r-project.org/package=optmatch

Examples

# make a sample data set
set.seed(1)
dat <- make_sample_data(n = 75)

# stratify with auto_stratify
a.strat <- auto_stratify(dat, "treat", outcome ~ X2, size = 25)

# 1:1 match based on propensity formula: treat ~ X1 + X2
# Requires optmatch package to be installed.

strata_match(a.strat, model = treat ~ X1 + X2, k = 1)


# full match within strata based on mahalanobis distance.
# Requires optmatch package to be installed.

strata_match(a.strat, model = treat ~ X1 + X2, method = "mahal", k = 1)