In an almost unreferenced article Carmichael (1928), writing of the period around the First World War, noted that “During the past twelve years many economic series have undergone what appears to be a permanent change in level.” These are prescient words that are widely applicable today....

The problem of optimal linear filtering, smoothing and trend extraction for m-period differences of processes with a unit root is studied. Such processes arise naturally in economics and finance, in the form of rates of change (price inflation, economic growth, financial returns) and finding an...

The development of the methods of correlation and regression analysis at the turn of the 20th century, led to their use in attempting to identify relationships between economic variables. However, caution was soon expressed that correlating series with ‘secular’ trends was likely to be...

This study evaluates a number of methods of reducing the bias and mean squared error of log-periodogram (LP) based methods to estimate the long-memory parameter and, in addition, assesses the actual coverage of the associated confidence intervals, considering both tails and the width of the...

Does theory aid inflation forecasting? To date, the evidence suggests that there is no systematic advantage of theory-based models of inflation dynamics over their astructural counterparts. This study reconsiders the issue by developing a “semi-structural” forecasting procedure comprised of...