Voting by Axioms Marie Christin Schmidtlein Abstract: How should we decide on the outcome of an election? Social choice theory offers many voting rules to answer this question, but also establishes various impossibility results showing that no single ideal rule exists. During recent years, researchers have developed a method for using axioms, i.e., desirable properties for voting rules, to justify or explain why a certain voting outcome is appropriate in a given scenario. This can be used to argue in favor of or against a specific voting rule’s behavior and shows that axioms can prescribe which outcome is to be returned in a certain situation. This thesis is dedicated to developing a novel decision procedure, Voting by Axioms, that takes decisions purely based on preselected axioms. That is, in each scenario, the voting rule returns the outcome that is justified or forced by the axioms that we care most about. The construction process sheds light on what axioms are and how to formalize them and we include a thorough analysis of the voting rule as well as an evaluation and possible generalizations of the framework in this thesis.