New Zealand’s academic research assessment scheme, the Performance Based Research Fund (PBRF), was launched in 2002 with the stated objective of increasing research quality in the nation’s universities. Evaluation rounds were conducted in 2003, 2006 and 2012. In this paper, we employ 22 different journal weighting schemes to generate output estimates of refereed journal paper and page production over three six year periods (1994-1999; 2000-2005 and 2006-2011). These time periods reflect a pre-PBRF environment, a mixed assessment period, and a pure PBRF research environment, respectively. Our findings indicate that, on average, research productivity, defined in either paper or page terms, has increased since the introduction of the PBRF. However, this outcome is due to a major increase in the quantity of papers and pages produced per capita that has more than off-set a decline in the quality of published outputs since the introduction of the PBRF. In other words, our findings suggest that the PBRF has failed to achieve its stated goal of increasing average research quality, but it has resulted in substantial gains in productivity achieved via large increases in the quantity of refereed journal articles.