Is There a q Factor in University Ranking?
Although the Shanghai rankings show a high correlation with other rankings (based on a tiny sample of US universities) the HEEACT rankings from Taiwan (Performance Ranking for Scientific Papers for World Universities) do somewhat better. The correlation with THE-QS is .740, the Shanghai ARWU .984, the USNWR America's best Colleges .711, Professional Ranking of World Universities .920 and the Center for College Affordability and Productivity .700.
All these rankings measure diffent things. The USNWR measures a variety of indicators related directly or indirectly to the quality of instruction, the CCAP is quite definitely a consumer-orintated ranking, the THES-QS World University Rankings are largely a measure of research performance (reputational survey, citations per faculty and student faculty ratio where researchers are counted in the faculty), the Professional Renking of World Universities counts CEOs of top companies while the Shanghai and Taiwan rankings focus entirely on research, mainly in the natural sciences.
The ability of the Taiwan rankings to predict scores on the other rankings suggests that underlying various measures of university quality is a single q factor, the average intelligence of its faculty. If there is one single number that would tell you about the general quality of a school than it would probably be the average IQ of the faculty, although performance on standardised tests, publications and citations (especially in the hard sciences) and postgraduate degrees might be goood proxies. The strength of the Taiwan rankings would be their focus on research productivity alone.
Incidently, if anyone from HEEACT reads this, please think of a new name for your rankings. PROSPWU is not exactly a memorable acronym.