The rescue of persecuted minorities - such as the Jews in Nazi occupied Europe - is seen in this paper as taking place in a peculiar market. In such a market rescuers face at least two dilemmas. Firstly, they might be willing to help but be uncertain how to go about rescuing. Secondly, they might be unsure over the nature of the request to help. To make a mistake and help "wrong" person could be very costly.
Following secondary analysis of the APPBI data on those who rescued Jews (rescuers) and those who did not (non-rescuers) during the Nazi occupation of Europe we find that (a) the first dilemma was solved by a direct request for help from those in need; (b) the second dilemma was solved by helping those who were either known to the rescuers, or sent by a trusted mediators.
We thus conclude that the unobserved acts of altruism in society do not account for the potential acts of altruism human beings are capable of. If the market for altruism works more efficiently, more people might be helped.