Match-Rigging in Professional Sumo-Elucidation of Incentive Structures and Empirical Analysis-
建立模型分析职业相扑中不同级别选手的假赛激励差异，实证发现顶级选手假赛在Duggan和Levitt（2002）后减少，训练级选手无统计显著的假赛，且丑闻后假赛降至不可检测水平，受罚选手确为参与最多者。
This paper first develops a simple model to show that incentives for match-rigging in professional sumo differ depending on the rank to which a wrestler belongs. While incentives for match-rigging can arise for wrestlers in the top divisions (sekitori), few incentives arise for wrestlers-in-training (makushita and below). We then report the results of our empirical analysis, which show that match-rigging in the top divisions has declined in the post-Duggan and Levitt (2002) period, and that at the wrestler-in-training level there was no statistically detectable match-rigging during any period. We find further that match-rigging in professional sumo has stabilized at statistically undetectable levels following the mobile phone text message match-rigging scandal, and that on average the wrestlers selected for sanctions following the scandal were in fact those most involved in match-rigging.