 In more recent years enthusiasm about TFT has been tempered by increasing skepticism.(See, for example, Binmore 2015 (p. 30) and Northcott and Alexandrova (pp. 71-78). Evidence has emerged that the striking success of TFT in Axelrod's tournaments may be partly due to features particular to Axelrod's setup. Rapoport et al (2015) suggest that, instead of conducting a round-robin tournament in which every strategy plays every strategy, one might divide the initial population of stratgies randomly into equal-size groups, conduct round-robin tournaments within each group. and then a championship round-robin tournament among the group winners. They find that, with the same initial population of strategies present in Axelrod's first tournament, the strategies ranked two and six in that tournament both perform considerably better than top-ranked TFT. Kretz (2011) finds that, in round-robin tournaments among populations of strategies that can only condition on a small number of prior moves (of which TFT is clearly one) relative performance of strategies is sensitive to the payoff values in the PD matrix. (Interestingly, this is so even if the PDs all satisfy or fail to satisfy the condition R+P=T+S, characterizing exchange games, and if they all satisfy or fail to satisfy the RCA condition, R&gt;½(T+S).  