Equity theory (ET) is an organizational theory investigating how fairly people feel they have been treated. The literature on ET does not address two essential questions: what is the magnitude of the equity that one may perceive compared to other members in an organization?, and how much should be the resources (outcomes) of an underpaid member reduced (increased) to feel equal? The group members may respond to these questions emotionally, and their answers could be biased based on their personalities. This paper proposes a novel method using data envelopment analysis (DEA) to quantify the ET and answer these questions more logically. DEA is a mathematical model that is conceptually similar to ET. We will show how DEA can estimate the degree of equity perceived by members of a group with different personalities, including optimistic, pessimistic, benevolent, and entitled characters.