The Decision Tree is an interactive learning tool enabling students to make a series of decisions in order to reach a conclusion. The software enables any branching decision process to be modelled so that students can interact with it, receive feedback, and improve their descision-making processes based on a series of non-linear pathways.

It is based on an adaptation of a diagram first presented to CAD by Siew Read from ELSAC. Students were shown the decision process used for prepositions on a specific noun. The diagrams originally appeared in a Powerpoint, which soon became a website.

With a Teaching Improvement Grant, the Department of Paediatrics has developed a small group of ‘evPaeds’ using the Decision Tree to simulate real-life clinical scenarios and assist students to develop clinical reasoning skills. Learners make diagnostic and therapeutic decisions as they gather information from patient history, examination and investigations.

The decision tree has two modes, a "play" mode for students to find a pathway through various questions and an "edit" mode where authors can add, delete or make changes to the descision trees in the exercise.