A woman in Jiegu in northwestern China and all she has to eat, a bowl of barley, after an earthquake destroyed her home in April. Despite several devastating natural disasters, China has dramatically reduced its rate of extreme poverty since 2007. FREDERIC J. BROWN/AFP/Getty

More than 1 in 5 people worldwide live in extreme poverty — defined by the World Bank as living on less than $1.25 per day — according to self-reported household income data released by Gallup on Monday.

Analyzing data from 131 countries compiled from 2006 to 2012, Gallup found that a third of respondents get by on less than $2 per day — sobering news for the World Bank, which has declared an ambitious goal of slashing the global extreme-poverty rate to just 3 percent by 2030.

The rate is dramatically higher than the world average in sub-Saharan Africa, where 54% of respondents from 27 countries live in extreme poverty. In Burundi and Liberia, the proportion is almost 90 percent.

Analysts note that Gallup employed a unique methodology using self-reported income rather than the laborious calculations of daily consumption — calories consumed, utility costs — used by the World Bank.

“It’s a much cruder attempt to obtain these numbers, and yet the results seem broadly in the same range,” said Laurence Chandy, a fellow in the Global Economy and Development program at the Brookings Institution. “So it seems that we can assume rough and ready estimates through a much less laborious process.”

By boiling down a household’s poverty to a single question, Chandy told Al Jazeera, Gallup might also have identified a relatively accurate method for charting progress in the global fight against poverty that can be reproduced quickly.

While more nuanced or technological methods can provide much-needed texture to information about global poverty — one particularly innovative measure involves looking at satellite imagery and counting streetlights as a proxy for a community’s relative wealth — a one-question survey can be deployed quickly and easily even in the poorest countries, which are sometimes surveyed only once a decade.