“…where H = {h 1 , ..., h H } ⊆ N H is a set of projection points such that h 1 < h 2 < · · · h H , y t+h is an endogenous variable observed at period t+h, α (h) is an intercept, z t is an exogenous variable observed at period t, w 1,t , ..., w J−2,t are covariates, which may include lags of the endogenous and exogenous variables, β (h) and γ j,(h) are unknown coefficients, and u (h),t+h is a residual. The model allows asymmetric and/or state-dependent impulse responses, as in Riera-Crichton et al (2015), Auerbach and Gorodnichenko (2013), and Ramey and Zubuairy (2018). The definition of y t+h and z t depends on whether the model is used for an impulse response analysis or forecasting.…”