R/crosscut.R

In DOS2: Design of Observational Studies, Companion to the Second Edition

crosscut <-
function(x,y,ct=.25,gamma=1,LS=FALSE){
  stopifnot(is.vector(x))
  stopifnot(is.vector(y))
  stopifnot(length(x)==length(y))
  stopifnot(is.vector(ct)&(length(ct)==1)&(ct>0)&(ct<=.5))
  stopifnot(is.vector(gamma)&(length(gamma)==1)&(gamma>=1))
  stopifnot(is.logical(LS))
	qx1<-stats::quantile(x,ct)
	qx2<-stats::quantile(x,1-ct)
	qy1<-stats::quantile(y,ct)
	qy2<-stats::quantile(y,1-ct)
	use<-((x<=qx1)|(x>=qx2))&((y<=qy1)|(y>=qy2))
	tb<-table(x[use]>=qx2,y[use]>=qy2)
	dimnames(tb)<-list(x=c("<=",">="),y=c("<=",">="))
	if (LS) o<-sensitivity2x2xk::mhLS(tb,Gamma=gamma)
	else o<-sensitivity2x2xk::mh(tb,Gamma=gamma)
	quantiles<-c(qx1,qx2,qy1,qy2)
	names(quantiles)<-c("x1","x2","y1","y2")
	list(quantiles=quantiles,table=tb,output=o)
}