There has been a steady growth in the number of national university league tables over the last 25 years. By contrast, "World University Rankings" are a more recent development and have received little serious academic scrutiny in peer-reviewed publications. Few researchers have evaluated the sources of data and the statistical approaches used. The present article seeks to address this gap. The authors explain and evaluate the methodologies used by the "Times Higher Education Supplement" and Shanghai Jiao Tong University, highlighting differences in their outcomes and in their degree of stability over time. A range of concerns must be addressed if such rankings are to inspire a level of confidence which transcends the established "infotainment" value of league tables (Bowden, 2000). (Contains 6 tables.)