help overdisp

Title

overdisp -- A direct command to detect overdispersion in count-data models

Syntax

overdisp depvar indepvars , level(#)

Description

overdisp provides a direct alternative to identify overdispersion in Stata, being a faster and an easier way to choose between Poisson and binomial negative estimations in the presence of count-data. Thus, overdisp can be implementd without the necessity of previously estimating Poisson or binomial negative models.

Options

level(#) specifies confidence level, and the default is level(95). H0 indicates equidispersion.

Examples

. overdisp docvis private medicaid age age2 educyr actlim totchr

. overdisp docvis private medicaid age age2 educyr actlim totchr, level(90)

References

Cameron, A. C., and P. K. Trivedi. 2010. Microeconometrics using Stata. Revised ed. College Station, TX: Stata Press.

Cameron, A. C., and P. K. Trivedi. 2013. Regression Analysis of Count Data. 2nd ed. Cambridge: Cambridge University Press.

Fávero, L. P., and P. Belfiore. 2017. Manual de Análise de Dados: Estatística e Modelagem Multivariada. Rio de Janeiro: Elsevier.

Fávero, L. P., and P. Belfiore. 2018. Data Science for Business and Decision Making. San Diego: Academic Press Elsevier.

Acknowledgment

We are especially grateful to Enrique Pinzon (StataCorp) for providing us with helpful suggestions and support.