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