Medicare Part D, which provides medications to 36 million Americans by giving seniors and the disabled access to prescription drugs, is often described as a healthcare success story, coming in below cost estimates.

But when ProPublica looked closely at Medicare's prescription data, they found hundreds of millions of dollars a year were being wasted — all because a small percentage of doctors prescribe name-brand drugs instead of lower-cost generics, even when the generics work just as well. Right here in New York City, these doctors could save Medicare over $50 million a year.

WNYC teamed up with ProPublica to find out: why? We started by visiting 1220 Avenue P in Brooklyn, the Levit Medical Center. If just six doctors at this one address prescribed in a different way, they could have saved Medicare $1.8 million dollars in 2011 alone.

Want to find out how your doctor is prescribing? Check out ProPublica's Prescriber Checkup. Type in a physician's name or zip code and you'll find out more about how physicians spend Medicare's money.

Versions of this story were co-published with public radio station WNYC in New York, with American Public Media’s Marketplace and with Digital First Media web sites and newspapers.