Publications of PhD Candidates
A data set giving the number of publications by doctoral candidates in biochemistry in relation to various predictors, originally from Long (1997).
There is a large number of zero counts. Is there evidence for a separate group of non-publishers?
data(PhdPubs)
A data frame with 915 observations on the following 6 variables.
articlesnumber of articles published in the final three years of PhD studies
femaledummy variable for gender, coded 1 for female
marrieddummy variable for marital status, coded 1 for married
kid5number of young children, age 5 and under
phdprestigeprestige of the PhD department. The higher the number the more prestigious the program.
mentornumber of publications by the mentor in the preceeding three years
In this version of the data set, phdprestige had been rounded to the nearest integer.
A Stata version with the continuous values was subsequently found at
https://www.stata-press.com/data/lf2/couart2.dta
Long, J. S. (1997). Regression Models for Categorical and Limited Dependent Variables, Sage.
Long, J. S. & Freese, J. (2006). Regression Models for Categorical Dependent Variables Using Stata, 2nd Ed., Stata Press.
data(PhdPubs)
# very uninformative
hist(PhdPubs$articles, breaks=0:19, col="pink", xlim=c(0,20),
xlab="Number of Articles")
library(vcd)
rootogram(goodfit(PhdPubs$articles), xlab="Number of Articles")
# compare with negative binomial
rootogram(goodfit(PhdPubs$articles, type="nbinomial"),
xlab="Number of Articles", main="Negative binomial")Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.