The diffusion of responsibility occurs when many people are equally morally responsible for the same thing. It often occurs in a corporate/business setting in which a major error is attributable to several minor errors up and down the corporate ladder. In other cases, it may produce the “bystander effect.” The bystander effect happens when many people let something bad unfold because each of them feels little individual responsibility (as a function of the number of bystanders). According to Singer, responsibility for global catastrophes is so diffuse that most people feel no responsibility at all. This leads to a kind of bystander effect because most people continue to do nothing in the face of serious moral emergencies like the suffering of the extremely poor.

Effective altruism is a movement within philanthropy that aims to maximize the cost-effective measures for alleviating the suffering of those in absolute poverty. The purpose of the effective altruism movement is not simply to do good by donating to decent causes; it is instead to achieve maximal results through the scientific evaluation of rigorously gathered data regarding the most efficient and effective aid organizations and programs.