Abstract for: Reflections on the Validity of T21 and PCM, System Dynamics Integrated National Development Planning Simulation Models
The impossibility to identify and represent events and emergent characteristics of the system analyzed with computer simulation models aimed at projecting future events has posed serious questions about their validity in the field of social science. While methodological issues, both concerning the foundations of the methodology and the formulation of models, are identified, the System Dynamics methodology seems to allow modelers to gain a deep understanding of the systems studied while answering the four dilemmas identified in this study. These models allow for the structural representation of the system through the identification of causal relations underlying its main functioning mechanisms, represent both dynamic and detailed complexity using wide social, economic and environmental boundaries. Dynamic simulation models are by no means perfect and will never be; nevertheless, modelers have the responsibility to use our best scientific understanding to develop reasonable and sustainable policies. T21 and PCM, integrated national development models, allow us to do so by enhancing the understanding of systems.