I am writing this letter to support Mr. Alfonso Ramon Sanchez Martin application for a Marie Curie Fellowship. I have known Alfonso for about 4 years now. I have been a Chair Professor of Economics at the Universidad Carlos III de Madrid during the period 1994-1999, before joining the Economics Department at the University of Minnesota. Alfonso has attended my classes in Economic Growth and Public Economics at Carlos III and has interacted with me frequently since then. He is currently working on his Doctoral Thesis, under the supervision of Professor Sergi Jimenez at Universidad Carlos III. Professor Jimenez is a co-author of mine in the areas of public policy and social security, hence I have had plenty of opportunities to follow and discuss the research work of Mr . Sanchez Martin. I have also examined his research work directly in various occasion, hence I feel comfortable to provide you with an evaluation of his abilities as a Doctoral student and of his potentials as a young researcher. Alfonso was certainly the best student in his class. He performed very well both in the classroom and in the tests, in both my courses and, to the best of my knowledge, also in all other classes he has taken at Carlos III. He is a mature person and a well trained applied economist , with an excellent technical background (arguably, with a superior technical background in econometrics, mathematics and computing) and a very good understanding of economics and its applications. He has also displayed a strong interest in applying frontier research tools to the understanding of important social and political problem. His Doctoral Dissertation topic is an excellent case in point. He is using modern dynamic general equilibrium theory coupled with advanced microeconometric and simulation techniques, to understand the basic determinants of labor supply over the life cycle and, in particular, during the late years of active life. His main concern is with the system of incentives to accumulate human capital, develop skill and supply labor over time induced by existing public pension and social protection systems. This is a topic of utmost social and political relevance, which is still poorly understood and on which a large research effort is being undertaken by academics and practitioners both in Europe and abroad. Alfonso has already made substantial contributions to this literature. I am confident that the period of research abroad he could enjoy with the support of a Marie Curie Fellowship would be greatly beneficial and would allow him a successful completion of the efforts he has undertaken. In terms of comparison, I consider Mr. Sanchez Martin one of the three best Doctoral students in the area of economics I have met at Carlos III since 1994, out of a total of about one hundred an twenty such students. The other two are Doctor Ana Montes, now a promising Assistant Professor at the Universidad de Murcia, and Doctor Ignacio Conde Ruiz, who, in this moment, is holding positions at IGIER (Universita^TM L. Bocconi, Milano, Italy) and at the Universidad Pompeu Fabra in Barcelona.