Zombie statistics are false facts that just never seem to die. Examples include such whoppers as “People use only 10% of their brains” and “You need to drink eight glasses of water a day”. Less obvious zombie statistics haunt researchers in every field and steps must be taken to kill them with fire.

Candice Helfand-Rogers reports on how zombie statistics can influence your thinking in this article from The Story Exchange:

Zombie statistics, simply put, are tidbits of information that are frequently cited by experts and institutions, despite having no basis in research or reality. And Kathryn Moeller at Stanford University found a big one: “When an educated girl earns income, she reinvests 90 percent in her family, compared to 35 percent for a boy.”

It’s something we’ve certainly heard a lot about in our work. But here’s the thing — when Moeller went digging for a source to this claim, she was never able to find one. Instead, she found various institutions citing one another, without any of them actually taking responsibility for researching the statistic.

When she discussed this with BBC World Service, she pointed out that this unsubstantiated item has been a “key piece of evidence” driving the creation and development of aid programs for girls and women — despite the lack of substance. “It brings up an important set of questions about data. We need valid, reliable gender data for policy-making.”

Moeller wrote about this phenomenon and its effects in greater depth for The New Yorker. “The rapid expansion of conditional cash transfer and micro-finance programs around the world … is based on the idea that giving money to women rather than men leads to significantly higher development returns,” she says.


As for Moeller, she did get the World Bank to remove the zombie statistic she discovered from their website. The Gates Foundation and the United Nations also told her they had stopped citing it. It’s an important step, but Moeller agrees that there are still very real economic inequalities faced by girls and women for those and other organizations to address.