Doctoral Publications

Description

Cross-section data on the scientific productivity of PhD students in biochemistry.

Usage

data("PhDPublications")

Format

A data frame containing 915 observations on 6 variables.

articles

Number of articles published during last 3 years of PhD.

gender

factor indicating gender.

married

factor. Is the PhD student married?

kids

Number of children less than 6 years old.

prestige

Prestige of the graduate program.

mentor

Number of articles published by student's mentor.

Source

Online complements to Long (1997).

References

Long, J.S. (1990). Regression Models for Categorical and Limited Dependent Variables. Thousand Oaks: Sage Publications.

Long, J.S. (1997). The Origin of Sex Differences in Science. Social Forces, 68, 1297–1315.

Examples

## from Long (1997)
data("PhDPublications")

## Table 8.1, p. 227
summary(PhDPublications)

## Figure 8.2, p. 220
plot(0:10, dpois(0:10, mean(PhDPublications$articles)), type = "b", col = 2,
  xlab = "Number of articles", ylab = "Probability")
lines(0:10, prop.table(table(PhDPublications$articles))[1:11], type = "b")
legend("topright", c("observed", "predicted"), col = 1:2, lty = rep(1, 2), bty = "n")

## Table 8.2, p. 228
fm_lrm <- lm(log(articles + 0.5) ~ ., data = PhDPublications)
summary(fm_lrm)
-2 * logLik(fm_lrm)
fm_prm <- glm(articles ~ ., data = PhDPublications, family = poisson)
library("MASS")
fm_nbrm <- glm.nb(articles ~ ., data = PhDPublications)

## Table 8.3, p. 246
library("pscl")
fm_zip <- zeroinfl(articles ~ . | ., data = PhDPublications)
fm_zinb <- zeroinfl(articles ~ . | ., data = PhDPublications, dist = "negbin")