In this paper we apply the statistical framework recently proposed by Imbens (1999) and Lechner (1999) to identify the causal effects of multiple treatments under the conditional independence assumption. We show that under this assumption, matching with respect to the ratio of the scores allows...

Using rules inspired by the statistics literature (Rubin (1976), Robins, Rotnitzky, and Zhao (1994) and (1995)), we formulate simple assumptions on the stochatic process by which firms or individuals exit from samples. Based on these hypotheses, we show that a simple adaptation of the GMM...

This paper studies the link between productivity, innovation and research at the firm level. We introduce three new features: (i) A structural model that explains productivity by innovation output, and innovation output by research investment; (ii) New data on French manufacturing firms,...