For animal health, developing such

For animal health, developing such frameworks for priority assessment represents an
enormous challenge. First, there is a myriad of disease problems Ð each affecting
particular species under certain conditions in different ways from threats of epidemics
with mortality, to insidious, productivity-lowering endemic infections. To consider the
full range requires assembling information on possibly hundreds of disease constraints.
Second Ð and more fundamental Ð is the nature of the decision criteria appropriate
for priority assessment. Anticipating the discussion in the following section on
decision-making, we generally perceive decision makers as performing priority
assessment for the purpose of choosing the diseases on which to focus their efforts in
improving control. Priorities are typically identified, therefore, on the basis of
economic benefit generated per dollar invested in improving control. Ideally, then,
decision-makers and stakeholders should have information at their fingertips about the
potential economic return associated with improving control for each of the full range
of relevant diseases, so that diseases could be ranked accordingly. In fact, though, there
are often multiple control options associated with each disease constraint, and each
option may be applied at varying degrees of intensity Ð so the decision criteria
become perpetually moving targets rather than quantifiable absolutes. It is interesting
to note that in the human health sphere, the estimated Disability-Adjusted Life Years
lost due to a disease is increasingly being used as a principal criterion for longer term
priority setting (Murray and Lopez, 1996). This total loss figure makes good sense
given that the undisputed objective is to eliminate all human loss and suffering. In the
livestock health sphere, on the other hand, the objective is to optimise economic
benefit with production losses generally being tolerated if there is insufficient
economic justification to reduce or eliminate them. The useful measure for
livestock health (as argued previously by McInerney (1996) and Perry and
Randolph (1999), among others), is therefore the economic value of avoidable losses
Ð which will vary depending on the level and type of control Ð rather than total
losses.