Mismeasuring long-run growth: The bias from spliced national accounts
Leandro Prados de la Escosura 27 September 2014
As demonstrated by the dramatic upward revision of Nigeria’s GDP for 2013, the choice of a benchmark year matters when computing GDP statistics. This column explains how the replacement of benchmark years creates an inconsistency between new and old national accounts series, and how different ways of resolving this inconsistency yield very different estimates of historical GDP levels and growth rates. When used to evaluate the relative historical performance of Spain and France, the interpolation procedure for splicing national accounts produces more plausible results than the conventional ‘retropolation’ approach.
In April it was made public that Nigeria’s GDP figures for 2013 had been revised upwards by 89%, as the base year for its calculation was brought forward from 1990 to 2010 (Financial Times, 7 April 2014). As a result, Nigeria became the largest economy in sub-Saharan Africa. Though spectacular, this is not an exceptional case. Ghana (2010), Argentina (1993), and Italy (1987) also experienced dramatic upward revisions of their GDP. How should this revision affect GDP time series and, consequently, the country’s relative position?
Development Economic history
GDP, GDP measurement, national accounts, statistics, measurement, measurement error, data
More to do on measuring hunger
Joachim De Weerdt, Kathleen Beegle, Jed Friedman, John Gibson 18 February 2014
Whereas the Millennium Development Goal of reducing extreme poverty by half was achieved by 2010, the global hunger rate has only fallen by a third since 1990. Differences in survey design may account for part of this discrepancy. This column presents the results of a recent experiment in which households were randomly assigned to different survey designs. These different designs yield vastly different hunger estimates, ranging from 19% to 68% of the population being hungry.
One of the first Millennium Development Goals is to reduce hunger by half between 1990 and 2015. To date, the global hunger count has fallen slightly, from 1 billion in 1990–1992 to 870 million in 2010–2012 (Food and Agriculture Organization 2013). As a proportion of the world’s population, this is just a one-third fall in the hunger rate, from 19% to 13%. In contrast, the other highly visible Millennium Development Goal – reducing extreme poverty by half – was achieved by 2010.
Poverty and income inequality
development, Africa, Poverty, Millennium Development Goals, food, hunger, measurement error, surveys, Tanzania