The history of the reforms of the assistance given to Australian agriculture over the past fifty years is a remarkable story, especially when contrasted with the experiences of most other OECD countries. The effects of these reforms have been captured by the Productivity Commission (and its predecessors) and by Lloyd through time series of the nominal rates of assistance to individual agricultural commodities and to the industry as a whole. In this paper the concept of a partial equilibrium production assistance index is developed to obtain a more accurate picture of the implicit welfare consequences of this assistance for the period 1955-59 to 2000-04. This index is a mean of order 2. It is shown that the conventional average, the mean of order 1, substantially underestimates the mean of order 2, which is the correct definition of the average level of assistance.