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MatchIt (version 1.0-1)

diagnose: Diagnostics for matching procedure

Description

diagnose is a sub-function of matchit which calculates summary statistics for the matching, including the weight for each unit.

Usage

diagnose <- diagnose(formula, match.matrix, pscore, in.sample, data, exact=FALSE,
		mahvars=NULL, subclass=0, psclass=NULL, nearest=TRUE, q.cut=NULL, counter=TRUE)

Arguments

formula
(required). Takes the form of T ~ X1 + X2, where T is a binary treatment indicator and X1 and X2 are the pre-treatment covariates, and T, X1, and X2 are contained
match.matrix
(required). n1 by ratio data frame where the rows correspond to treated units and the columns store the names of the control units matched to each treated unit. NA indicates that treated unit was not matched. Generally created in nearest.
pscore
(required). Vector of estimated propensity scores. Generally calculated in distance.
in.sample
(required). Vector of length n showing whether each unit was eligible for matching due to common support restrictions with discard. Generally calculated in distance.
data
(required). Data frame containing the variables called in the formula. The dataframe should not include variables with the names psclass, psweights, or pscore, as these are expressly reserved in the o
exact
"FALSE" (default)=no exact matching. "TRUE"=exact matching on all variables in formula. A vector of variable names (that are in data to indicate separate variables on which to exact match, in combination with matching on the pr
mahvars
Variables on which to perform Mahalanobis matching within each caliper (default=NULL). Should be entered as a vector of names of variables in data.
subclass
Either a scaler specifying the number of subclasses (default=0) or a vector of probabilities to create quantiles based on sub.by.
psclass
Subclass index in an ordinal scale from 1 to the number of subclasses. Unmatched units have subclass=0. Generally computed in subclassify.
nearest
Whether to perform nearest-neighbor matching (default=TRUE).
q.cut
Subclass cut points. Generally calculated in subclassify.
counter
Whether to display counter indicating the progress of the matching (default=TRUE).

Value

  • psweightsVector of length n giving the weight assigned to each unit in the matching process. Each weight is proportional to the number of times that unit was matched.

Details

This is a sub-function of matchit which calculates summary statistics for the matching procedure in matchit, calculating t-statistics for covariates as well as weights for each unit. This function is called directly by matchit and does not generally need to be called directly by users; these details are included for advanced users.

See Also

Please use help.matchit to access the matchit reference manual. The complete document is available online at http://gking.harvard.edu/matchit.