Unit Roots and Structural Change: An Application to US House-Price Indices

This paper employs unit-root tests that allow for two endogenous breaks as suggested by Lumdaine and Papell (1997) and Lee and Strazicich (2003) to investigate the returns on the S&P/Case-Shiller Home Price Indices. The tests that assume structural stability provide no evidence against the unit-root hypothesis in all returns series. Conversely, the Lumdaine-Papell and Lee-Strazicich tests indicate that significant structural breaks exist. Only the Lee-Strazicich test, however, which incorporates structural changes under the null hypothesis, finds that the returns to houses exhibit trend stationarity with structural breaks, in most cases, rather than a random walk. Following Meen (1999), we also investigate the stationarity of the metropolitan house-price ratios. The findings of the Lumsdaine-Papell test provide no evidence against the unit-root hypothesis in all house-price ratio series. Conversely, the Lee-Strazicich test finds broken-trend stationarity of the metropolitan house-price ratios for Boston, Miami, and New York.