The Parable of the Piano Teacher

In April’s column on creating habit, the timing of return office visits was touted as a tool doctors can use to change patients’ behaviors. The differences in return visits between clinical trials (where visits come frequently) and clinical practice (where visits are much less common) account for variances in the efficacy and tolerability of medications in these settings. This is perhaps best illustrated by the parable of the piano teacher.

A piano teacher met with her students once a week for eight to 12 weeks at which time there was a piano recital. All the kids sounded terrific. They played the piano well at the recital because they had practiced every week.

Another piano teacher, realizing that it was the practicing and not the weekly visits that made the kids play so well, told his students, “Kids, we’re going to have a recital in eight to 12 weeks, but we’re going to skip the weekly lessons. The lessons don’t matter. What makes you play well is practice. Just practice every day, and you will play well at the recital.”

That recital sounded terrible because the kids didn’t practice much at all until just three days before the recital. Without the weekly lessons to encourage adherence to piano practice, the kids just didn’t practice.

Clinical trials will often describe how fast the drug worked, showing statistically significant changes in outcomes as early as one to two weeks after starting on the drug. A beautiful curve is shown with data points every two to three weeks, displaying how the disease continues to gradually improve over eight to 12 weeks or longer. The FDA approves the drug, and the package insert describes how the drug is well tolerated and how a large fraction of patients achieve benefit in eight to 12 weeks. So the doctor prescribes the drug and says, “Come back in eight to 12 weeks.” Patients often return frustrated that the drug didn’t work as expected or have tolerability issues that they couldn’t put up with for eight to 12 weeks which caused them to discontinue treatment entirely.

This is the Heisenberg Uncertainty Principle at work: Measuring outcomes in a clinical trial changes those outcomes because the visits to measure the outcome change people’s adherence behavior. The effect is dramatic!1 If you don’t believe in the power of this principle, just see if you floss your teeth more often than usual before your next dental appointment. If you are marketing a new drug and looking for a way to keep patients adherent to that drug, then do what you can to mimic the effect of those clinical trial visits.2


1. Turchin A, Goldberg SI, Shubina M, Einbinder JS, Conlin PR. Encounter frequency and blood pressure in hypertensive patients with diabetes mellitus. Hypertension. 2010; 56:68-74.

2. Causa Research,

  • Steven Feldman, M.D.

    Dr. Steven Feldman is Professor of Dermatology and Public Health Sciences at Wake Forest Baptist Medical Center. Steve studies patient adherence at North Carolina’s Wake Forest Baptist Medical Center. He is also Chief Science Officer of Causa Reseach, an adherence solutions company (, founder of, and author of “Compartments” and “An Illustrated Dictionary of Behavioral Economics for Healthcare Professionals.”


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