Given the political sensitivities of the topic, it is hard to imagine that a suitably rigorous attempt to answer this question could be organized or its results published and discussed soberly, but it is striking that there is no serious basis on which to conduct such a conversation. Religion brings peace and solace to many; religion kills people, divides societies, diverts energy and resources. How to assess the net impact in some meaningfully quantitative way? Even to imagine the possibility of such an inquiry and to think through some of the categories you would use could be very enlightening.