Maxim Pinkovskiy, Xavier Sala-i-Martin, 26 June 2016

When it comes to measuring GDP, researchers tend to use the latest vintage of the Penn World Tables. However, competing series like the World Development Indicators (WDI) and changing methodologies between vintages mean this is not necessarily the best approach. This column assesses the relative performance of different GDP estimators using night-time lights as an unbiased predictor of the growth rates of unobserved true income. Newer versions of the Penn Tables are not necessarily improvements on their direct predecessors.  Newer versions of the WDI index, especially the 2011 vintage, appear generally better at measuring cross-country income differences.

Angus Deaton, Bettina Aten, 16 July 2014

When the international comparison project published its latest estimates of purchasing power parity exchange rates in April there was some consternation. Poor countries became richer overnight, world GDP increased, and global income inequality was revised downwards. Alas, no one stopped being poor. This column digs into the numbers to see if we’ve been consistently underestimating the relative size of poorer economies and overestimating global poverty and inequality.

Clara Capelli, Gianni Vaggi, 06 March 2014

The GNI is often regarded as the best indicator of a country’s living standards, but it does not record unilateral transfers – most importantly remittances – which are amongst the largest types of income inflows to developing countries. For many developing countries GNDI is significantly larger than GNI, from 3% for India to 75% for Liberia. This column argues that GNDI is preferable, since GNI masks heterogeneity in purchasing power.