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Food Allergies TrueNorth Survey

A hand holds up a shrimp
Using innovative methods to track Americans’ food allergies
  • Client
    Northwestern University Feinberg School of Medicine, in collaboration with the University of Southern California and Stanford University
  • Dates
    2015 - 2016


Food allergies are notoriously difficult to quantify. 

Scientists researching the public costs of food allergies needed to find a sampling method that was large and precise enough to determine national prevalence rates of both common and rare food-related sensitivities, as well as the age of onset for both. Researchers also need better information on the demographics of allergy sufferers and the under-prescription of life-saving epinephrine to those with elevated risks. To address these needs, the Northwestern University Feinberg School of Medicine tasked NORC with surveying a large number of Americans.


NORC’s TrueNorth® blended-survey approach painted a clearer food allergy picture.

We surveyed 7,000 participants in the rigorous, probability-based AmeriSpeak® Panel and augmented those results with 40,000 non-probability surveys administered to adults across the country. Then we used our state-of-the-art TrueNorth calibration system to conform the less rigorous online survey data to AmeriSpeak’s standards. Our weighting methodology used small-area estimation and iterative proportional fitting methods to correct for bias and variance. This approach provided both the reach and the precision required by the food allergy study.


We delivered scientifically significant—and newsworthy—findings.

Using NORC data, researchers published a 2019 JAMA article that for the first time reported 19 percent of Americans believe they have food allergies—but only about half of them (nearly 11 percent) reported “convincing” evidence they do. Of those 26 million Americans with such evidence, 38 percent have visited an emergency room because of a reaction.

Researchers were able to calculate prevalence rates, with allergies to shellfish at 2.9 percent and allergies to fin fish at 0.9 percent.

The research made headlines in The New York Times, U.S. News & World Report, Physician’s Weekly, Healthline, and on CNN and CBS.

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