National development planning is a decision process at the central government level that defines the strategic plan for a country’s long-term development. The System Dynamics Group at the University of Bergen in collaboration with Millennium Institute and the University of Iowa is developing an interactive learning environment for national development planning. BLEND is the acronym for Bergen Learning Environment for National Development. BLEND is a networked computer learning environment that constitutes a microcosm for real planning settings where policy makers play roles in a simulated government. The simulation model underlying BLEND is based on Millennium Institute’s Threshold 21 model (T21) which has so far been applied in over 20 countries. T21 is a rather large model with a high level of detail. There is, however, ample evidence that learning environments are more effective when the models are simplified. The purpose of this paper is therefore to identify the key learning goals that BLEND has to address. Based on these we develop a simplified version of T21 that exhibits a lower level of detail and eliminates non-fundamental structural components.