Many people who espouse effective altruism call themselves "effective altruists". In 2017 Marsh wrote "Good for Nothing" about the topic of altruists and psychopaths. Altruists discriminate between the individuals they help and favor relatives. Philosophically, wild animal suffering may be an additional moral concern for effective altruists. Siegel works with over 100 such altruists around the world. He then asks what happens to the proportion of altruists in the population. Earning to give has been proposed as a possible strategy for effective altruists. In 2000 Cahill performed in Nicky Silver's Off-Broadway production of "The Altruists". "The Altruists" by Craig Baxter, won the fourth STAGE International Script Competition. The research she coauthored studied "extraordinary altruists", using people who donated kidneys to strangers.