“…Knowing which countries get poorer, relative to other countries, also allows one to study the origins of these negative developments. Explanations for the African bgrowth tragedyQ that have been put forward in the literature are diverse, including geographic location, ethnic diversity, choice of institutions, political instability, bad public policy, insufficient infrastructure, limited openness to international trade, and the lack of social capital, see Easterly andLevine (1997, 2003), Sachs and Warner (1997), Bloom and Sachs (1998), Temple (1998), Collier and Gunning (1999a,b), Acemoglu et al (2001), Azam et al (2002), and Artadi and Sala-i-Martin (2003), among others. In the present paper, we will not investigate the sources of economic growth in detail, although our model is well-suited for this purpose, especially for exploring the issue of parameter heterogeneity, which means to say that the marginal impact of certain growth determinants might be different across (groups of) countries.…”