Probabilistic decision modelling to determine impacts on natural resource management and livelihood resilience in Marsabit County, Kenya.

Published online
14 Aug 2019
Content type

Tamba, Y. & Muchiri, C. & Luedeling, E. & Shepherd, K.

Publication language
Africa South of Sahara & Kenya


Decision makers, from the household to state level, are frequently faced with decisions that need to be made within a context of risks, uncertainties, multiple possible outcomes and stakeholder groups with varied interests. Business decision analysis methods offer a promising solution because they have been designed to aid businesses in making decisions on risky projects with limited research budgets. The decision analysis approach applied at ICRAF supports decision-making by evaluating business cases and simulating the impact of proposed investments using participatory and probabilistic tools to quantify the potential costs, benefits and associated risks of interventions while accounting for uncertainty in order to realistically forecast the range of plausible project outcomes. A decision analysis exercise was commissioned by the International Union for Conservation of Nature (IUCN) under the "Integrated plan to enhance socioeconomic and ecological resilience of the wider Huri Hills and Shurr Plains landscapes, Marsabit Kenya" project. The purpose was to evaluate the business case for selected investments to improve water availability and access in each landscape. To build comprehensive quantitative models for the proposed investments, the analysts simulated the impact pathways of interventions identified by the local communities that would enhance their resilience. From this information, the analysts conceptualized the models, seeking confirmation on the models' logic from community discussions and implementing partners. The analyses provided initial approximations of the overall net benefits of three interventions in Huri Hills and Shurr. It also revealed trade-offs, especially between environmental and socioeconomic effects, that would require careful consideration by local decision makers. These reflections could be supported by targeted measurements to narrow the identified critical knowledge gaps. Such additional measurements were recommended as the next step to reducing uncertainty, not only on the highlighted key input variables, but also on the projected outcomes. This would improve decision makers' ability to decide on whether tank construction is desirable from an overall impacts point of view in Shurr, and which, if any, of the investment alternatives at Huri Hills is likely to achieve the goals of the programme. As illustrated in this case study, the decision analysis approach is valuable as a tool for monitoring and learning, allowing the community and project implementers to study the actual performance of the investments against the projected performance during their implementation.

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