The outcome of some football matches has benefited both teams at the expense of a third team because head-to-head results were used for breaking ties. Inspired by these examples, our mathematical analysis identifies all possible collusion opportunities caused by this particular ranking rule in a...

When social pressure leads to favoritism, policies might aim to reduce the bias by affecting its source. This paper shows that multiple sources may be present and telling them apart is important. We build a novel and granular dataset on European football games and revisit the view that and...