The aim of this study was to examine age-related differences in decision-making competence. The study is a part of the ongoing Betula project (Nilsson et al., 1997; 2004), and the data included test results from (N, 364) corresponding to the questionnaires with complete responses (>80%) to the items addressed. The Swedish version of the Adult Decision-Making Competence (A-DMC) battery was used. An exploratory factor analysis of the A-DMC data yielded a two-component solution: The A-DMC tasks were divided into Factor 1 (Applying Decision Rules, Resistance to Framing and Consistency in Risk Perception tasks), and Factor 2 (Under/Overconfidence, Resistance to Sunk Costs and Recognizing Social Norms). These two factors showed opposite age effects, where Factor 1 (analytic decision making) declined with age, whereas Factor 2 (heuristic decision competence) was not negatively affected by old age. / Betula Project