An avalanche of articles has described the testing of a time series for the presence of unit roots. However, economic model builders have disagreed on the value of testing and how best to operationalise the tests. Sometimes the characterization of the series is an end in itself. More often, unit...

When we first began publication of the Journal of Forecasting, we reviewed policies that were used by other journals and also examined the research on scientific publishing. Our findings were translated into a referee's rating form that was published in the journal [Armstrong (1982a)]. These...

Unit-root testing can be a preliminary step in model development, an intermediate step, or an end in itself. Some researchers have questioned the value of any unit-root and cointegration testing, arguing that restrictions based on theory are at least as effective. Such confusion is...