Agricultural extension professionals are aware of the complexity surrounding farmers’ decisions to adopt a new technology or practice. These extension officers often need to design strategies to improve adoption though planning processes, which are commonly run collaboratively by expert groups and through deliberation rather than individually. Models have been used to assist these deliberations, but it is not clear which aspects of the model or the deliberative process are more useful for extension planning. In this study, we research how ADOPT, a model that predicts adoption, may assist decision making in planning for agricultural extension. In 2018, we used ADOPT in three workshops with extension officers from the pastoral sector in New Zealand to analyse the adoption of four well-known practices in the industry. We identified important features of the model and the process used in the workshops and asked participants to rank their usefulness. The components were: a conceptual model of adoption, a comparison between the predicted diffusion curve and actual uptake, a sensitivity analysis of the results, and a structured discussion around these components. We found that using ADOPT changed participants’ perceptions on the feasibility of forecasting adoption. We also found that participants believe the process of discussing and using ADOPT was just as important, or more important, than the model’s results.