Semiparametric estimation of information technology diffusion models: A study based on portuguese firm-level data

This paper applies both parametric and semiparametric methods to the estimation of an Information Technologies (IT) Diffusion Model for Portuguese firms. The semiparametric estimator used is the one proposed by Klein, and Spady (1993). Specification tests based on the findings of Horowitz and Härdle (1994), Fan, and Liu (1997) and Aït-Sahalia, Bickel, and Stoker (2001) are employed to verify the goodness of fit of the parametric model. We find that both approaches yield similar results and specification tests reveal that the estimated parametric model fits the data reasonably well and can therefore be used for policy purposes.