1\name{DoctorVisits}
2\alias{DoctorVisits}
3
4\title{Australian Health Service Utilization Data}
5
6\description{
7Cross-section data originating from the 1977--1978 Australian Health Survey.
8}
9
10\usage{data("DoctorVisits")}
11
12\format{
13A data frame containing 5,190 observations on 12 variables.
14\describe{
15  \item{visits}{Number of doctor visits in past 2 weeks.}
16  \item{gender}{Factor indicating gender.}
17  \item{age}{Age in years divided by 100.}
18  \item{income}{Annual income in tens of thousands of dollars.}
19  \item{illness}{Number of illnesses in past 2 weeks.}
20  \item{reduced}{Number of days of reduced activity in past 2 weeks due to illness or injury.}
21  \item{health}{General health questionnaire score using Goldberg's method.}
22  \item{private}{Factor. Does the individual have private health insurance?}
23  \item{freepoor}{Factor. Does the individual have free government health insurance due to low income?}
24  \item{freerepat}{Factor. Does the individual have free government health insurance due to old age,
25          disability or veteran status?}
26  \item{nchronic}{Factor. Is there a chronic condition not limiting activity?}
27  \item{lchronic}{Factor. Is there a chronic condition limiting activity?}
28}
29}
30
31\source{
32Journal of Applied Econometrics Data Archive.
33
34\url{http://qed.econ.queensu.ca/jae/1997-v12.3/mullahy/}
35}
36
37\references{
38Cameron, A.C. and Trivedi, P.K. (1986). Econometric Models Based on Count Data:
39Comparisons and Applications of Some Estimators and Tests.
40\emph{Journal of Applied Econometrics},
41\bold{1}, 29--53.
42
43Cameron, A.C. and Trivedi, P.K. (1998). \emph{Regression Analysis of Count Data}.
44Cambridge: Cambridge University Press.
45
46Mullahy, J. (1997). Heterogeneity, Excess Zeros, and the Structure of Count Data Models.
47\emph{Journal of Applied Econometrics},
48\bold{12}, 337--350.
49}
50
51\seealso{\code{\link{CameronTrivedi1998}}}
52
53\examples{
54data("DoctorVisits", package = "AER")
55library("MASS")
56
57## Cameron and Trivedi (1986), Table III, col. (1)
58dv_lm <- lm(visits ~ . + I(age^2), data = DoctorVisits)
59summary(dv_lm)
60
61## Cameron and Trivedi (1998), Table 3.3
62dv_pois <- glm(visits ~ . + I(age^2), data = DoctorVisits, family = poisson)
63summary(dv_pois)                  ## MLH standard errors
64coeftest(dv_pois, vcov = vcovOPG) ## MLOP standard errors
65logLik(dv_pois)
66## standard errors denoted RS ("unspecified omega robust sandwich estimate")
67coeftest(dv_pois, vcov = sandwich)
68
69## Cameron and Trivedi (1986), Table III, col. (4)
70dv_nb <- glm.nb(visits ~ . + I(age^2), data = DoctorVisits)
71summary(dv_nb)
72logLik(dv_nb)
73}
74
75\keyword{datasets}
76