cem (version 1.0.128)

imbspace.plot: Plot of imbalance space diagnostic tool for CEM

Description

Plot of imbalance space diagnostic tool for CEM

Usage

imbspace.plot(obj,group="1")

Arguments

obj

an object of class imbalance.space

group

character string denoting group id. Defaults to "1".

Value

• tab
  an invisible object containing the selection of cem solutions and their coarsenings.

Details

For an interactive device a two panels plot is given. On the left panel the user can select a CEM solution and the number of cutpoints used in that matching solution is plotted as a parallel plot on the right plot. On exit (right-click on the left panel), the function returns all the cem solutions highlighted in the last selection of the user.

For non-interactive devices, only the space of the solutions are plotted.

This plot shows the tradeoff in matching as a function of imbalance and sample size.

The imbalance of the raw data is represented as a red plot and the initial CEM solution as a green plot. All solutions below the green dot and left to it are better than the user choice in terms of imbalance and number of units matched.

References

Stefano Iacus, Gary King, Giuseppe Porro, ``Matching for Casual Inference Without Balance Checking: Coarsened Exact Matching,'' http://gking.harvard.edu/files/abs/cem-abs.shtml

See Also

imbspace

Examples

require(cem)

data(LL)

mat <- cem("treated", LL, drop=c("re78","treated"), cut=list(age=4, edu=4, re74=3, re75=3))
mat

imb.raw <- L1.profile(LL$treated, LL[, mat$vars], M=250, plot=FALSE)

imbsp <- imbspace(mat, LL,depth=2, raw.profile=imb.raw, maximal=6, minimal=2, fixed=c("hispanic", "black", "married", "nodegree","u74","u75"), plot=FALSE)

tmp <- plot(imbsp)
tmp