y¯ctτ+∑τ=12αbetween,τ∑r≠cdcr−1y¯rtτ+∑τ=12ρτz¯tτ+xctβ+𝜖ct.Model A
We also consider more parsimonious model specifications, such as the model that only considers within-city transmissions, 2 yct=∑τ=12αwithin,τ