Clinical Decision Support Systems (CDSSs) and Patient Decision Aids (PDAs) are increasingly used in clinical practice. Their effectiveness is judged using different outcome measures. For example, PDAs are evaluated using decisional regret, decisional conflict and decision quality as outcome measures. This project investigates how these outcome measures relate to patient autonomy. For as PDAs systematically influence the decision-making process, we need to make sure that the different outcome measures we use to evaluate PDAs scientifically align with our ethical principles.