trade-off matrix (n)~ A tool for managing project trade-offs by portraying them in a matrix that reflects the three project variables (presented on the y axis) in the context of three decisions (presented on the x axis). The project variables are resources (people and money) schedule (time) and features (the product and its quality). These variables are sometimes presented as the trade-off triangle. The three decisions are whether to optimize constrain or accept a given variable. A change to one of the project variables requires that the team make a correction on one of the three sides to maintain project balance including potentially the same side on which the change first occurred. For example a decision to add a feature to a product may require that other features be removed if sufficient time and resources are unavailable to support their development.