When studying particular subgroups of a population, like for instance lone parents, the econometrician typically has few observations at hand. In such a situation, it is vital to take advantage of any valid complementary information that may be available. In this paper we illustrate, for the...

During the past few decades, the interest of economists in the sources of long-term economic growth has led an increasing number of them to focus on the role of innovation in creating that growth. Although some researchers have always been interested in this topic, the groundbreaking work of...