Concept 9: Decision models

The decisions made by farmers regarding pest management are determined by the four factors shown in the figure below:

• problem, in terms of the pest, the level of attack, and the damage caused,

• options available to the farmer, such as cultural practices, resistant crop varieties or breeds of livestock, and pesticides,

• farmer's perceptions of the problem and of the availability and effectiveness of the options, and

• farmer's objectives, including monetary goals and his or her attitude to financial risks, health hazards, and community values.

We need to understand how the variables in this decision model influence the actual pest control decisions made by producers if our research and extension effort is most likely to succeed.  Thus, interviews with farmers are often concerned with determining the actual control practices that they carry out, and why - for instance, are they aware of alternatives, how do they make their decisions, and what is their perception of the potential loss caused by the pest?

This decision model can also provide a valuable framework for looking at the decision problems that face policy makers, extension agents and research scientists.  For instance, consider the questions that need to be asked in designing an R & D strategy for plant breeding.  In deciding on a particular strategy aimed at producing a variety that incorporates disease resistance, rather than one of a number of other possible features, the plant breeder needs to consider a number of factors, including an assessment of the likely adoption of the variety if it is successfully produced, requiring consideration of the factors that affect why farmers choose the particular varieties and disease control practices they employ at present.  Thus, a key question that arises is - "What features will the new variety need to have in order to be a feasible and desirable option that farmers will adopt?"   This provides a specified target at which the breeder needs to aim.