This paper puts forward a method to estimate average economic growth, andits associated confidence bounds, which does not require a formal decision onpotential unit root properties. The method is based on the analysis of eitherdifference-stationary or trend-stationary time series models,...

The popular 'airline' model for a seasonal time series assumes that a variable needs double differencing, i.e. first and seasonal (or annual) differencing. The resultant time series can usaually be described by a low order moving average model with estimated roots close to the unit circle. This...