In this paper we provide evidence on the presence of seasonal unit roots in aggregate U.S. data. The analysis is conducted using the approach developed by Hyllebcrg, Engle, Granger and Yoo (1990). We first derive the mechanics and asyrnptotics of the HEGY procedure for monthly data and use Monte...

This paper provides technical documentation to accompany the NBER manufacturing productivity (MP) database. The database contains information on 450 4-digit manufacturing industries for the period 1958 through 1991. The data are compiled from various official sources, most notably the Annual...