Treating the sniffles or a common cold with drugs is ineffective and unnecessary, yet too often patients are leaving their doctors’ appointments with a prescription in hand, helping to fuel the epidemic of antibiotic resistance. But one cheap and apparently effective approach is making inroads at a small number of Los Angeles clinics.

A new randomized control study reports that a simple fix – having clinicians sign a poster-sized commitment letter stating they will only prescribe drugs when it lines up with prescription guidelines, and then displaying the pledge alongside the clinician’s photograph in exam rooms – reduced inappropriate antibiotic prescription practices during flu season by about 20 percent.

The findings appear in the January 27 JAMA Internal Medicine. The theory behind this success, the authors say, is that the providers made both personal and public commitments to tamp down inappropriate prescription practices (rather than just posting a guideline reminder, a tactic that has not been as effective as this one).

“Our hypothesis is that this commitment device is a key difference between our intervention and past work,” says lead author Daniella Meeker, a scientist at the RAND Corporation focusing on health and behavioral economics. Exactly why this approach worked— whether doctors perhaps felt more at ease saying no to drug requests because the poster was visible or they perceived patient demands differently— remains unclear. The posters did not bring about changes in drug prescribing altogether; fortunately, there was not a drop in how often clinicians provided the appropriate drugs or a shift in how doctors documented practices for making appropriate diagnoses.

The success with this cheaper approach may now turn heads in the research community. The cure for flawed prescription practices has long eluded medical experts, despite varied efforts to combat the problem. Consider that about half of all antibiotics in the U.S. are inappropriate or not needed, according to the U.S. Centers for Disease Control and Prevention. And the toll from that misuse can be staggering. Antibiotic resistance, attributed to drug misuse in various settings, boosts health care costs every year by an estimated $20 billion and may cost another $35 billion in lost productivity. This work also helps to underscore the magnitude of the problem: both clinicians with and without the posters still had concerning levels of inappropriate prescribing. Providers who did not have the signed posters increased their inappropriate prescribing rates by almost 10 percent during the intervention period, whereas those who had signed the commitment letter reduced unnecessary prescriptions by about 10 percent. That left the improved clinicians still inappropriately providing drugs roughly a third of the time (although some of that number likely includes appropriate prescriptions that were not fully apparent from studying the coded electronic health records but could have been detected by looking at chart data).

Clearly, this study does not ultimately settle the matter. It’s still small – there were only seven providers in the group without the posters and seven providers with the posters. That means these findings would have to be replicated on a larger scale, and researchers would need to explore whether there were any differences in prescribing practices, say, between what nurse practitioners and physicians did. But if this approach triggered similar responses in other settings, the authors say it could theoretically eliminate 2.6 million unnecessary prescriptions and save $70.4 million in drug costs across the country.

Check out the commitment letter here, available in both English and Spanish: