The Subjective Dynamic Decision Model (SDEM): A New Approach to Decision-Making Under Radical Uncertainty

This paper develops a hybrid model for strategic decision-making in contexts of radical uncertainty. It combines the formal structure of game Theory with the epistemological principles of the Austrian School of Economics. The Subjective Dynamic Decision Model (SDEM) describes decisions not as the result of rational optimisation, but as the result of subjective perception, heuristic action strategies and iterative learning processes. The focus is on modelling the subjective decision-making state, consisting of information, conviction and expectation. Decisions arise from this through experience-based heuristics and are modified by observed results. In addition to the theoretical derivation, the article also provides concrete applications in the areas of cyber security, market behaviour and intelligence work. Simulation-based analyses are used to show how adaptive decision-making strategies develop in complex environments. While generalisability to real-world settings may be limited due to reliance on simulation, SDEM enables practical scenario modelling in volatile domains where traditional optimisation fails. The aim is not to describe optimal solutions, but to analyse subjective adaptation processes in non-linear decision-making contexts. The model thus stands for an insight-oriented approach to decision research