Even apart from differences in adoption, on-farm benefits of a given agricultural research outcome vary widely. They vary between different farming regions due to differences in climate and soils, between different farmers due to differences in their experience, skills, risk attitudes, perceptions, wealth and resources, and between different paddocks of any given farm due to differences in soil type, topography, soil fertility and weed burden. The issue of aggregation is completely ignored in virtually all BCAs done for GRDC, because it is time consuming and difficult. If the aim is to improve scientists' understanding of their potential contributions to the farming system, these complexities can be sidestepped to some extent. The issues can be dealt with, but not in a lowly resourced process with very tight deadlines.
Standardisation is much touted, but it does nothing to overcome the difficulties outlined here.
Indeed, it serves only to sweep them under the carpet. One cost is the obvious one of time spent doing the analyses. This is always hard to establish, but it suffers greatly when scientists feel that, due to economists, they have had thrust upon them requirements to participate in over-simplistic and rather mechanical analyses, based mainly on guesswork. It is true that not all scientists react so negatively, but many do. I do believe strongly in the potential value of research evaluation, but not in the current GRDC system.