1\name{occup} 2\alias{occup} 3\docType{data} 4\title{ A small occupational cohort } 5\description{This is the data that is behind the illustrative Lexis 6diagram in Breslow & Day's book on case-control studies.} 7\usage{data(occup)} 8\format{ 9 A data frame with 13 observations on the following 4 variables. 10 \describe{ 11 \item{\code{AoE}}{a numeric vector, Age at Entry} 12 \item{\code{DoE}}{a numeric vector, Date of entry} 13 \item{\code{DoX}}{a numeric vector, Date of eXit} 14 \item{\code{Xst}}{eXit status \code{D}-event, \code{W}-withdrawal, 15 \code{X}-censoring} 16 } 17} 18\references{ 19Breslow & Day: Statistical Methods in Cancer Research, vol 1: 20The analysis of case-control studies, figure 2.2, p. 48.} 21\examples{ 22data(occup) 23lx <- Lexis( entry = list( per=DoE, age=AoE ), 24 exit = list( per=DoX ), 25 entry.status = "W", 26 exit.status = Xst, 27 data = occup ) 28plot( lx ) 29# Split follow-up in 5-year classes 30sx <- splitLexis( lx, seq(1940,1960,5), "per" ) 31sx <- splitLexis( sx, seq( 40, 60,5), "age" ) 32plot( sx ) 33 34# Plot with a bit more paraphernalia and a device to get 35# the years on the same physical scale on both axes 36ypi <- 2.5 # Years per inch 37dev.new( height=15/ypi+1, width=20/ypi+1 ) # add an inch in each direction for 38par( mai=c(3,3,1,1)/4, mgp=c(3,1,0)/1.6 ) # the margins set in inches by mai= 39plot(sx,las=1,col="black",lty.grid=1,lwd=2,type="l", 40 xlim=c(1940,1960),ylim=c(40,55),xaxs="i",yaxs="i",yaxt="n", 41 xlab="Calendar year", ylab="Age (years)") 42axis( side=2, at=seq(40,55,5), las=1 ) 43points(sx,pch=c(NA,16)[(sx$lex.Xst=="D")+1] ) 44box() 45# Annotation with the person-years 46PY.ann.Lexis( sx, cex=0.8 ) 47} 48\keyword{datasets} 49