This paper proposes a general framework for analyzing diversity in science, technology, and society. It identifies three essential but individually insufficient properties of diversity: variety, balance, and disparity. Based on 10 quality criteria, the paper suggests a non-parametric diversity heuristic, $\mathcal{D}$, which allows systematic exploration of diversity under different perspectives and trade-offs. The heuristic is designed to be flexible and applicable across various fields, including conservation management, research governance, energy policy, and sustainable innovation. The paper illustrates the practical application of this framework in examining relationships between diversity and other issues, such as portfolio interactions. The approach aims to provide a more systematic and transparent way to handle scientific and technological diversity, addressing challenges related to aggregation, accommodation, and articulation of diversity with other system properties.This paper proposes a general framework for analyzing diversity in science, technology, and society. It identifies three essential but individually insufficient properties of diversity: variety, balance, and disparity. Based on 10 quality criteria, the paper suggests a non-parametric diversity heuristic, $\mathcal{D}$, which allows systematic exploration of diversity under different perspectives and trade-offs. The heuristic is designed to be flexible and applicable across various fields, including conservation management, research governance, energy policy, and sustainable innovation. The paper illustrates the practical application of this framework in examining relationships between diversity and other issues, such as portfolio interactions. The approach aims to provide a more systematic and transparent way to handle scientific and technological diversity, addressing challenges related to aggregation, accommodation, and articulation of diversity with other system properties.