RBA Annual Conference – 2015 Equation (1)

S I_{i j t}^{o v e r a l l} = {\begin{array}{l} 1 if Δ B_{i j t} \leq 0 & and & Δ T_{i j t} \leq 0 (negative complementary relationship) \\ 2 if Δ B_{i j t} \leq 0 & and & Δ T_{i j t} > 0 (substitution) \\ 3 if Δ B_{i j t} > 0 & and & Δ T_{i j t} \leq 0 (substitution) \\ 4 if Δ B_{i j t} > 0 & and & Δ T_{i j t} > 0 (positive complementary relationship) . \end{array}