Nutrition report cards are a feasible and efficient way to motivate children to eat healthier at school, a study by Cornell University behavioral economists finds.

The study “Nutrition Report Cards: An Opportunity to Improve School Lunch Selection,”  appears in the online journal Plos One. Brian Wansink and David Just are the main authors.

Over five weeks of the pilot study, 27 parents in a rural New York district received a weekly e-mail listing meal, snack and ala carte foods chosen by their child. Choices were analyzed before as well as during that period.

With the report cards in place, the percent of students choosing cookies dropped from 14.3% to 6.5%. The cards didn’t provide a grade, but simply recorded and totaled choices.

Student purchase data on fruits and vegetables prior to implementing the report cards were not available, so a before and after comparison was not included. But children of parents receiving the cards chose produce items somewhat more often than a control group.

Though generating the cards required new keys on check-out registers, checkout times rose just 0.16 seconds per transaction. Compiling and sending the report cards took 30 minutes of staff time weekly, according to the research.

“Although the results are preliminary, they suggest that (nutrition report cards) may be helpful in nudging children toward more healthy, less expensive options … at little cost to the school district,” Wansink and Just say in the study.

The report cards prompted more in-home discussions about food and nutrition, according to parents who participated.