Michael D. Bauer, James Hamilton, 07 July 2017

Several recent empirical papers have challenged the ‘spanning hypothesis’, which holds that the level, slope, and curvature of bond yield curves are sufficient to forecast returns and estimate bond risk premia This column argues that these studies suffer from a previously unrecognised standard error bias. Controlling for this bias, false positives are found to be between six and twelve times more likely, suggesting that the evidence against the spanning hypothesis is substantially less convincing than would appear from the studies.

James Hamilton, 22 June 2017

In economic research, the Hodrick-Prescott filter is a widely used tool for removing cyclical components from time-series data. This column argues that, despite its popularity, the HP filter has serious drawbacks that should severely restrict its application. It involves several levels of differencing, so that for random walk series, subsequently observed patterns are likely to be artefacts of having applied the filter, rather than due to the underlying data-generating process. The column goes on to suggest an alternative to the HP filter that avoids these pitfalls. 

Caitlin Brown, Dominique van de Walle, Martin Ravallion, 30 March 2017

Policymakers face challenges when trying to identify the right targets for antipoverty programmes. This column assesses whether the data typically available to policymakers in sub-Saharan Africa are up to the task. Commonly used proxy means tests are found to perform worse than simpler methods in identifying poor households. Moreover, analyses of nutritional status reveal substantial inequality within households, suggesting that household-based measures are not very effective in identifying disadvantaged individuals.