We test for a unit root in postwar unemployment rates for sixteen OECD countries. When a one-time structural break is incorporated, the unit root hypothesis can be rejected for most of the countries and the measured persistence of unemployment falls dramatically. We then test for multiple structural changes and find evidence of one or two breaks for those countries for which the unit root hypothesis could be rejected. Almost all of the breaks are positive, reflecting the sustained rise in European unemployment. The major exception is the United States, where long-term unemployment rose in the 1970s and fell in the 1980s.

This paper proposes an explicit test for determining the significance and the timing of slowdowns in economic growth. We examine a large sample of countries and find that a majority—though not all—exhibit a significant structural break in their postwar growth rates. We find that (a) most industrialized countries experienced postwar growth slowdowns in the early 1970s, though (b) the United States, Canada, and the United Kingdom did not, and (c) developing countries (and in particular, Latin American countries) tended to experience much more severe slowdowns which, in contrast with the more developed countries, began nearly a decade later.

Ever since Nelson and Plosser (1982) found evidence in favor of the unit-root hypothesis for 13 long-term annual macro series, observed unit-root behavior has been equated with persistence in the economy. Perron (1989) questioned this interpretation, arguing instead that the “observed” behavior may indicate failure to account for structural change. Zivot and Andrews (1992) restored confidence in the unit-root hypothesis by incorporating an endogenous break point into the specification. By allowing for the possibility of two endogenous break points, we find more evidence against the unit-root hypothesis than Zivot and Andrews, but less than Perron.