So what did they find?
Well, firstly, size doesn't matter, much. Instead, the biggest determinants of research productivity are the diversity of fields (within economics) that your colleagues work on - higher diversity being good for productivity - and the degree of heterogeneity of publication quality within the department - more heterogeneity being bad for productivity. So, a mixed bag of apples and oranges (in terms of research interests) is good, but a few rotten apples do appear to spoil the bunch!
Apart from size, it is also interesting to note that the authors found little or no effect of proximity to other economics departments, a finding in contrast with the conventional wisdom from economic geography, which tends to find large agglomeration effects in economic productivity (e.g. comparing urban and rural areas).
Other interesting findings the authors report:
- Contrary to common intuition, more students per academic do not reduce publication performance.
- Women, older academics, stars in the department and co-authors in foreign institutions all have a positive externality impact on each academic's individual outcome.