Most public extension organizations worldwide operate on inadequate budgets. Extension field surveys, therefore, need to be as cost-efficient as possible. The study investigated the comparative contributions of mediating and independent variables to the adoption of co-financing of the delivery of public extension visits. A semi-structured, self-administered questionnaire was used to collect information from 97 small-scale crop farmers in the Free State province of South Africa, from 1 September to 7 October 2010. Non-probability sampling techniques were employed to select respondents. The mediating variables were found to contribute more to the adoption of co-financing for the delivery of public extension visits than the independent variables. Need tension, especially the difference between aspired and present situation with regard to practice adoption and production efficiency made the most individual contributions to the variation in adoption of co-financing for the delivery of public extension visits. Adoption behaviour analysis could therefore be focussed on a limited number of mediating variables in surveys. Focussing adoption behaviour investigations on the more direct precursors of behaviour can reduce extension survey costs. This also offers opportunities for generating extra funds to deliver optimal extension visits to farmers. While quantifying the savings is the subject of future research, there are strong grounds for concluding that they are considerable.