Comparación del modelo COM-Poisson y el modelo Poisson
Comparison of the COM-Poisson model and the Poisson model
Abstract (en)
When modeling count data, the poisson model is typically used, in which the equidispersion (ED) assumption is assumed, where the mean and variance are equal. When this condition is not easy to justify, different alternatives have been proposed, some more flexible than others in terms of accounting for both overdispersion (OD) and underdispersion (UN). One of them is the COM-Poisson model which was recently proposed and has been evaluated in inferential terms. The investigation presented here aims to compare the COM-Poisson model predictive quality with respect to the Poisson model and establish the loss in efficiency that occurs when the inadequate model is fitted when the property of equidispersion is not satisfactory. A simulation study determined that adjusting the inappropriate model either over or underdispersion does not represent in most cases, a gain or loss of the predictive quality. Two case studies illustrate ours findings obtained here.
Abstract (es)
La modelación de datos de conteo se hace típicamente usando el modelo Poisson, en el cual se asume equidispersión (ED), en donde la media y la varianza son iguales. Cuando esta condición no es fácil de justificar, han surgido diferentes alternativas, unas más flexibles que otras, en cuanto a la capacidad de manejar tanto sobredispersión (OD) como subdispersión (UD). Una de ellas es el modelo COM-Poisson el cual fue propuesto recientemente y ha sido evaluado en términos inferenciales (Sellers2010). Esta investigación quiere cuantificar la calidad predictiva del modelo COM-Poisson con respecto al modelo Poisson, y así establecer la pérdida en la eficiencia que se tiene al ajustar el modelo inadecuado cuando la propiedad de equidispersión no es satisfactoria. El estudio de simulación efectuado determinó que al ajustar el modelo inadecuado, ya sea en sobre o subdispersión, no representa, en la mayoría de los casos, ni una ganancia o pérdida en cuanto a la calidad predictiva de los valores ajustados. Dos estudios de caso aplicados a la ecología ilustran los resultados obtenidos
References
Forecasting Methods: Empirical Comparisons', 8(1), 69-80.
*http://dx.doi.org/10.1016/0169-2070 (92)90008-W
Cameron, A. C. & Trivedi, P. K. (2003), Essentials of Count Data Regression,
in B. H. Baltagi, ed., `A Companion to Theoretical Econometrics', Blackwell
Publishing Ltd, pp. 331-348.
*http://dx.doi.org/10.1002/9780470996249.ch16
Cameron, A. & Trivedi, P. K. (1998), Regression Analysis of Count Data, Cambridge
University Press, New York.
Dobson, A. J. (2002), An introduction to generalized linear models, 2nd ed. edn,
Chapman & Hall/CRC.
*http://dx.doi.org/10.1002/sim.1493
Famoye, F. (1993), `Restricted generalized poisson regression model', Communications
in Statistics - Theory and Methods 22(5), 1335-1354.
*https://doi.org/10.1080/03610929308831089
Francis, R., Geedipally, S. R., Guikema, S. D., Dhavala, S. S., Lord, D. & Larocca,
S. (2012), `Characterizing the Performance of the Conway-Maxwell Poisson
Generalized Linear Model', Risk Analysis 32(1), 167-183.
*https://doi.org/10.1111/j.1539-6924.2011.01659.x
Geedipally, S. R., Guikema, S. D., Dhavala, S. S. & Lord, D. (2008), Characterizing
the Performance of the Bayesian Conway-Maxwell Poisson Generalized Linear
Model, in A. S. Association, ed., `Joint Statistical Meetings', p. 22.
Guikema, S. D. & Go_elt, J. P. (2008), `A Flexible Count Data Regression Model
for Risk Analysis', Risk Analysis 28(1), 213-223.
*http://doi.wiley.com/10.1111/j.1539-6924.2008.01014.x
Hilbe, J. (2011), Negative Binomial Regression, 2nd ed. edn, Cambridge University
Press.
*https://doi.org/10.1017/CBO9780511973420
Jowaheer, V. & Mamode, N. (2009), `Estimating Regression E_ects in Com Poisson
Generalized Linear Model', World Academy of Science, Engineering and
Technology 29(1), 1040-1044.
Lord, D., Geedipally, S. R. & Guikema, S. D. (2010), `Extension of the Application
of Conway-Maxwell-Poisson Models: Analyzing Tra_c Crash Data Exhibiting
Underdispersion', Risk Analysis 30(8), 1268-1276.
*http://dx.doi.org/10.1111/j.1539-6924.2010.01417.x
Lord, D., Guikema, S. D. & Geedipally, S. R. (2008), `Application of the
Conway-Maxwell-Poisson generalized linear model for analyzing motor vehicle crashes', Accident Analysis and Prevention 40(3), 1123-1134.
*https://doi.org/10.1016/j.aap.2007.12.003
McCullagh, P. & Nelder, J. (1972), Generalized linear models, 2nd ed. edn, Chapman
& Hall/CRC, New York.
Miller, J. (2007), Comparing Poisson, Hurdle and ZIP model _t under varying degrees of Skew and Zero-Ination, Ph.d. thesis, University of Florida.
Minka, T. P., Shmueli, G., Kadane, J. B., Borle, S. & Boatwright, P. (2003),
Computing with the COM-Poisson distribution, Technical report, Carnegie
Mellon University, Pittsburgh, PA.
*http://repository.cmu.edu/statistics/170/
R Core Team (2017), R: A Language and Environment for Statistical Computing,
R Foundation for Statistical Computing, Vienna, Austria.
*https://www.R-project.org/
S_aez-Castillo, A. & Conde-S_anchez, A. (2013), `A hyper-Poisson regression model for overdispersed and underdispersed count data', Computational Statistics
& Data Analysis 61, 148-157.
*http://dx.doi.org/10.1016/j.csda.2012.12.009
Sellers, K. F., Borle, S. & Shmueli, G. (2012), `The COM-Poisson model for count data: A survey of methods and applications', Applied Stochastic Models in
Business and Industry 28(2), 104-116.
*http://dx.doi.org/10.1002/asmb.918
Sellers, K. F. & Shmueli, G. (2010a), `A exible regression model for count data',
Annals of Applied Statistics 4(2), 943-961.
*http://www.jstor.org/stable/29765537
Sellers, K. F. & Shmueli, G. (2010b), `Predicting Censored Count Data with COMPoisson
Regression', SSRN Electronic Journal p. 18.
*http://dx.doi.org/10.2139/ssrn.1702845
Shmueli, G., Minka, T., Kadane, J., Borle, S. & Boatwright, P. (2005), `A Useful
Distribution for Fitting Discrete Data: Revival of the Conway-MaxwellPoisson
Distribution', Journal of the Royal Statistical Society. Series C (Applied
Statistics) 54(1), 127-142.
*https://doi.org/10.1111/j.1467-9876.2005.00474.x
Winkelmann, R. (2008), Econometric Analysis of Count Data, 5th ed. edn,
Springer-Verlag, Berlin.
How to Cite
License
The authors maintain the rights to the articles and therefore they are free to share, copy, distribute, execute and publicly communicate the work under the following conditions:
Recognize the credits of the work in the manner specified by the author or licensor (but not in a way that suggests that, you have their support or that they support your use of their work).
Comunicaciones en Estadística is licensed under Creative Commons Atribución-NoComercial-CompartirIgual 4.0 Internacional (CC BY-NC-SA 4.0)
Universidad Santo Tomás preserves the patrimonial rights (copyright) of the published works, and favors and allows the reuse of them under the aforementioned license.