Past exam of the mathematics course of the University of Cambridge / 2018 / ii / Paper 4 / 13J / a

No intercept should be included unless the ordering of the two teams has an external meaning such as home advantage. Ifthen reversing the teams gives ${\eta }_{k\ell ,ij}=-{\eta }_{ij,k\ell }$, so the logistic model automatically givesAn intercept would not change sign when the teams are swapped and would violate this required symmetry. Thus an intercept does not make sense in the stated model.