The proportional reduction in the error of predicting the column category from the row (tau_col_given_row) and the reverse (Hedderich, Sachs & Reynarowych 2023, eqs 3.9-3.10): tau_C|R = (n sum_ij n_ij^2 / n_i. - sum_j n_.j^2) / (n^2 - sum_j n_.j^2).
The proportional reduction in the error of predicting the column category from the row (tau_col_given_row) and the reverse (Hedderich, Sachs & Reynarowych 2023, eqs 3.9-3.10): tau_C|R = (n sum_ij n_ij^2 / n_i. - sum_j n_.j^2) / (n^2 - sum_j n_.j^2).