Heterodox Academy aspires to create college classrooms and campuses that welcome diverse people with a wide spectrum of viewpoints and equip learners with the habits of heart and mind to engage in open inquiry and constructive disagreement. We see an academy eager to welcome professors, students, and speakers who approach problems and questions from different points of view, explicitly valuing the role such diversity plays in advancing the pursuit of knowledge, discovery, growth, innovation, and the exposure of falsehoods. Achieving this vision will necessitate a culture shift in campus communities and the students, professors, administrators, and staff who compose them. We have identified five individual-level characteristics that would help to bring about this goal:

1. Increased empathy and perspective-taking
2. Increased curiosity
3. Increased open-minded cognition
4. Increased intellectual humility
5. Decreased self-censorship

This toolkit describes how we (a) identified these individual characteristics, (b) determined appropriate measures of these individual characteristics, and (c) validated these measures for use among undergraduate students. It also contains these measures so that campus stakeholders can use them to determine the specific individual characteristics that relate to open inquiry, viewpoint diversity, and constructive disagreement on their own campuses.