By Will Martin and Hassan Zaman, guest bloggers
We are delighted that Derek Headey has introduced new data and new approaches into the debate on the impacts of higher food prices on food security. But we have difficulty with his claim that the results from Gallup World Poll (GWP) contradict the results from simulation studies for 2008 and subsequent years. There are, after all, two key methodological differences between the income-poverty impacts from food-price simulations and ex-post measures of food security.
The first is that food-price simulations ask whether changing food prices alone hurt or help the poor. By contrast, changes in the GWP data reflect changes in all relevant factors between 2005-6 and 2007-8. The simulations are potentially useful because changes in food prices may be influenced by quite different policies than other shocks, and may have large impacts on poverty.
A second methodological difference is that poor people are often forced to make up for a fall in real income due to higher prices, as measured by simulations, with some very costly adjustments in order to maintain a basic level of food intake as measured by the GWP data. These adjustments may include selling assets; borrowing at high interest rates; taking children out of school; and shifting towards foods that provide basic caloric needs at the expense of the dietary diversity so crucial for nutritional outcomes.
Even with these methodological differences, we still find the GWP result of a decline of 400 million in food-insecure people between 2005-6 and 2007-8 surprising. This is a large decline when we know that global food prices spiked in 2007-8; that the poorest households spend 60-70% of their income on food; and that energy prices were also rising. One question is whether the twelve month recall data for this Gallup survey covers the peak of the price rises? We look forward to analyzing more recent household survey data to assess the extent of poverty and food security changes—both of basic food intake and of dietary diversity—during this and subsequent periods.