Near-Integrated Data and the Analysis of Political Relationships

The Impact of News Media Favorability and Candidate Events in Presidential Campaigns

“…The issue of nonstationarity is especially disconcerting; although I am examining a short, bounded series, DeBoef and Granato (1997) point out that these data often mimic the non-stationary properties of integrated data and require remedy. To achieve stationarity and address concerns about serial autocorrelation, this study differences the noncategorical variables.…”

Forecasting real exchange rate trends using age structure data – the case of Sweden

“…This does not, however, exclude the possibility that a regression is spurious as shown byDeBoef and Granato (1997).…”

Political Science Research Methods in Action

“…Few other concepts in time series cause me as much conceptual and existential uncertainty and as many sleepless nights as that of unit root. There is long-standing argument among methodologists concerning whether political time series contain a 'unit root' (i.e., are integrated) or, instead, are fractional, near-integrated, or stationary processes (e.g., Beck, 1992, Box-Steffensmeier and Smith, 1996, De Boef, 2000, De Boef and Granato, 1997, Lebo et al, 2000, Wlezien, 2000 4 -that is, whether the effect of shocks to variables are additive and are therefore preserved in observations in future time periods. In non-technical jargon, unit root relates to whether a variable -such as public opinion or public policy -has a memory, insomuch as it is the sum of past values of itself plus random variation.…”

“…In addition to this, linear regressions of integrated and near-integrated series are also susceptible to spurious inferences (Granger andNewbold, 1974, De Boef andGranato, 1997) finding significant relationships where none exist. The alternative of differencing integrated variables to make them stationary is problematic as it removes information about the long-run relationships.…”