| plot.xbal {RItools} | R Documentation |
A plot method for xBalance objects. WORK IN PROGRESS. PATCHES AND CODE SUGGESTIONS APPRECIATED.
We aim this plot to be a diagnostic tool rather than a publication quality presentation tool.
## S3 method for class 'xbal':
plot(x,adjustxaxis=.25,segments=TRUE,legend=TRUE,
mar=c(3,3,2,0)+0.1,mgp=c(1.5,.5,0),tck=-.01,
which.strata=dimnames(x$results)[["strata"]],thestratalabs=which.strata,
which.stats="std.diff", ##dimnames(x$results)[["stat"]],
which.vars=dimnames(x$results)[["vars"]],thevarlabs=which.vars,
thexlab="Standardized Differences",
thecols=rainbow(length(which.strata)),
thesymbols=c(19,22,23,24,25)[1:length(which.strata)],...)
x |
An object of class "xbal" — the result of a call to xBalance() |
adjustxaxis |
amount by which the x-axis should be expanded. |
segments |
Should thin horizontal lines be plotted connecting the statistics for the different stratifications. |
legend |
Should a legend be plotted? |
mar |
Preliminary margin setting |
mgp |
Preliminary setting for axis labels |
tck |
Length of the tick marks |
which.strata |
The stratification candidates to include in the printout. Default is all. |
thestratalabs |
The text labels for the strata. |
which.stats |
a character vector of length 1. The test statistics to include. Default is the standardized difference. |
which.vars |
The variables for which test information should be displayed. Default is all. |
thevarlabs |
The text labels for the variables. |
thexlab |
The label for the x-axis (should tell viewers about the statistic chosen). |
thecols |
A vector of colors either (a) one per strata or (b) one for all strata. |
thesymbols |
A vector of plotting symbols either (a) one per strata or (b) one for all strata. |
... |
other arguments to the plot.default function setting up the plotting region. |
The plot allows a quick visual comparison of the effect of different
stratification designs on the comparability of different
variables. This is not a replacement for the omnibus statistical test
reported as part of print.xbal. But, it does allow the
analyst an easy look at which variables might be the primary culprits
of overall imbalances and/or a way to assess whether certain important
covariates might be imbalanced even if the omnibus test reports that
the stratification overall produces balance.
data(nuclearplants)
xb0<-xBalance(pr~ date + t1 + t2 + cap + ne + ct + bw + cum.n,data=nuclearplants)
plot(xb0)
xb1<-xBalance(pr~ date + t1 + t2 + cap + ne + ct + bw + cum.n,
strata=data.frame(unstrat=factor(character(32)),
pt=factor(nuclearplants$pt)),
data=nuclearplants,
report=c("adj.means","adj.mean.diffs","std.diffs", "z.scores", "chisquare.test","p.values"))
plot(xb1)