Is the time dimension really important in research into contracting out?

In a recent study into the literature, Bel and Fageda (2007) highlighted the lack of the time dimension in research dealing with explanatory factors in the decision to contract out municipal services. In this paper we attempt to evaluate if the argument of Bel and Fageda is true. We do this by means of two methodological contrasts in the designing of variables from a dataset containing 744 municipalities in Southern Spain. From our empirical analysis, we conclude that the consideration of the time dimension does contribute to a better specification of the model, and not considering it could lead to a misunderstanding of the motivation behind the decision.