This milestone report (MS 15) presents findings from Task T5.2 of the RE-INTEGRATE project (Horizon Europe, Grant No. 101118217), which investigates how the objectives, interests, and power of different actors involved in modelling activities influence the design, assumptions, and outputs of quantitative models at the science–policy interface. Focusing on the RE-INTEGRATE national case studies of Ethiopia and Zambia, the study builds on survey responses from stakeholder workshop participants and interviews with modelling team members. Insights from this task aim to inform scenario design, model development, and future applications in both the case study countries and in similar contexts.