Based on regularly published data we quantitatively assess the efficiency of UK secondary, private schools in providing quantity vs. quality of graduates on a per output basis. In economic terms the primary question is whether indeed an increase in the quantity of graduates with the observed inputs would be associated with a deterioration of average quality of graduates. The estimation framework is a new, statistically enriched type of Data Envelopment Analysis as detailed in Gstach (2002) to account for output-specific efficiencies. The results indicate that quantity clearly dominates quality as performance distinguishing criteria amongst sample schools, i.e. on average quantity efficiency is low while quality efficiency is high. The results also provide evidence that the abilities of schools to provide quantity resp. quality are positively correlated. These findings indicate considerable scope for increasing the number of graduates without sacrificing average graduation quality through improved school management. (author's abstract) / Series: Department of Economics Working Paper Series