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MULTIVARIATE SARMANOV COUNT DATA MODELS
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  • Abstract: I develop two flexible models of multivariate, count data regression that overcome several difficulties to extend Poisson regressions beyond the univariate case: i) account for both over and underdispersion, ii) allow for correlations of any sign among counts, iii) correlation and dispersion depend on different parameters, and iv) estimation is computationally feasible. I address whether the pricing strategies of competing duopolists in the early U.S. cellular telephone industry are strategic complements or substitutes. I show that a Sarmanov model with double Poisson marginals outperforms a count data model based on a multivariate renewal process with gamma distributed arrival times.

  • Publication: Previously circulated as CEPR DP No. 7463.

  • JEL: C16, C35, L11.

  • First version: June 2008.

  • Current version: September 2009.

  • Funding: None.

  • Seminars: None.

  • Conferences: Texas Camp Econometrics XIV (2009).

  • Presentation: PDF.

  • Media Citations: None.