A key tenet of effective altruism is that people should use evidence to identify the best ways to do good (Effective Altruism 2016). However, there is some disagreement among philosophers, other academics, and laymen concerning how this notion should be understood.
Many philosophers have a broad conception of evidence, according to which not only direct observations and other kinds of empirical data, but also for example a priori arguments count as evidence.
Others, however, use the term more narrowly, to refer specifically to empirical evidence—and in particular to empirical evidence produced by careful studies such as randomized controlled trials. Some members of the effective altruism community seem to have this second interpretation in mind when talking of effective altruism being concerned with evidence.
Effective Altruism. 2016. Introduction to effective altruism.
Kelly, Thomas. 2014. Evidence. In Edward Zalta (ed.), Stanford encyclopedia of philosophy.
Snowden, James. 2015. Why effective altruism used to be like evidence-based medicine. But isn’t anymore.
Argues that evidence should be interpreted more narrowly as empirical evidence, and that effective altruism should focus on this evidence.