This paper utilises a human-capital approach for ranking the research productivity of academic departments. Our approach provides rankings in terms of residual research output after controlling for the key characteristics of each department's academic staff. More specifically, we estimate residual research output rankings for all of New Zealand's economics departments based on their publication performance over the 2000 to 2006 period. We do so after taking into account the following characteristics of each department's academic staff: gender, experience, seniority, academic credentials and academic rank. The paper demonstrates that the rankings generated by the residual research approach and those generated by traditional approaches to research rankings may be significantly different for some departments. These differences are important in determining the likely efficiency impact of research assessment exercises.