“…Differential models are often estimated with intercepts and other variables, including a number of transition functions designed to capture taste shifts and other structural changes into the intercepts of structural and vector autoregressive demand models (e.g., Tsurumi, Wago, and Ilmakunnas, 1986; Moschini and Meilke, 1989; Goodwin, 1992; Goodwin and Brester, 1995; Rickertsen, 1995; Moschini and Moro, 1996; Deschamps, 2003; Jouini and Boutahar, 2005; Holt and Craig, 2006). Most of the transition function specifications are capable of capturing only unidirectional shifts.…”