To eradicate (or at least reduce) hunger, information on who is hungry, where, and why, and what the trends are is absolutely essential.

Marc Cohen is a Senior Researcher on Humanitarian Policy at Oxfam America.

How many hungry people are there in the world? How do we know? Does it matter?

These questions have come up repeatedly since the 1996 World Food Summit declared the global goal of reducing the number of hungry people in the world (from 1990 levels) by half by 2015. The Summit charged the Food and Agriculture Organization of the United Nations (FAO) with measuring progress in achieving the goal.

Over the past 15 years, FAO’s measurements of “food insecurity in the world” have come under repeated criticism for either understating or overstating the numbers.

The problem, FAO’s critics agree, was that the agency focused too much on national calorie availability, calculating how many people lacked the calories needed for “minimal activity.” FAO used a statistical model to factor in how the calories would be distributed, but often based on guestimates or very old studies of income inequality.

Another problem was that the global and country-level estimates say nothing about inequality within a country. So if China dramatically reduces hunger nationally, but still has tens of millions of hungry people in its impoverished Western interior, that doesn’t show up in the numbers. Nor did FAO’s reports look at important issues like who eats first and most within households, where there’s frequently gender and age discrimination. Finally, FAO wasn’t factoring in vitamin and mineral deficiencies, which affect over a billion people, have severely negative public health consequences, and undermine sustainable development.

Last October, FAO released the latest installment of its flagship publication, The State of Food Insecurity in the World, with a brand-new methodology that incorporates results from household surveys to better measure access to food and get beyond a focus on just calorie availability.

Using the new methods, FAO reported that hunger was much higher than previously estimated back in 1990. And, the agency found that hunger has been slowly declining ever since, without the previously reported big jump in the number of hungry people as a result of higher food prices in 2007-08. However, slower global economic growth since then has reduced the pace at which hunger has declined.

A group of US and Canadian scholars and anti-hunger activists, organized by Oxfam Sister on the Planet Frances Moore Lappé, recently issued a critique of FAO’s latest food insecurity report. Among other things, the critics appropriately take the agency to task for continuing to focus on calories and minimal activity. In addition, they point out that FAO considers “hungry” to mean calorie deficient for at least a year, and so excludes the hunger impact of short-term price spikes.

The critics also object to FAO’s emphasis on the role of economic growth in eliminating hunger, which leaves out things like the right to food, empowerment of hungry people, governments’ accountability to their citizens, unequal access to productive resources (such as land and jobs), and the public policies needed to tackle the causes of hunger. FAO does say that growth is necessary but not sufficient. The critics retort that these “other things” get lost from the report’s main message, which is all about growth.

This debate begs the question: do the numbers matter, and if so, why?

The numbers do matter. There is wide agreement that hunger in a world of plenty is an assault on human rights and dignity. World leaders have repeatedly endorsed the goal of eradicating (or at least reducing) hunger. To accomplish this, information on who is hungry, where, and why, and what the trends are is absolutely essential.

But this raises even more questions. Will FAO’s members—that is, the world’s nation states, and especially the rich ones—invest the resources necessary to create precise hunger numbers? And, once we have those numbers on hand, will governments do the right thing with them and put eliminating hunger high on the policy agenda?