A properly sized spoon helps the medicine go down without unintended side effects, finds a new study by two marketing researchers, published in the Annals of Internal Medicine.

"Prone to error, spoon dosing of medicine is one of the leading causes of pediatric poisonings," says Georgia Tech marketing assistant professor Koert van Ittersum, who conducted the study with Brian Wansink, a marketing professor at Cornell University. "While the Food and Drug Administration recommends against kitchen silverware to dose liquid medicine, a majority of people still use spoons when pouring medicine for themselves and family members."

In their study, the researchers found that people dosed 8.4 percent less than prescribed into medium-sized spoons and 11.6 percent more into larger utensils. Yet, study participants (195 university students) had above-average confidence that they'd poured the correct dosage. "Although they were young, educated, and had poured in a well-lit room following a practice pour, these participants were still unaware of these biases," the researchers write. "Whereas the clinical implications of an 8-12 percent dosing error in a single-teaspoon serving of medicine may be minimal, the dosing error is likely to accumulate among fatigued patients who are medicating themselves every four to eight hours for a number of days."

Based on their findings, the researchers recommend that patients or caregivers use a measuring cap, dosing spoon, measuring dropper, or dosing syringe for accuracy instead of relying on their estimating abilities. While one might expect more experienced pourers such as nurses and practiced patients to be more accurate in their estimations, this might not be the case, the researchers note.

Wansink and van Ittersum have previously conducted related research showing veteran bartenders are inconsistent about the amount of liquor they pour, depending upon the type of glass used (over-pouring into short, wide glasses).