Narrator:       This is Science Today. A UCLA study has found that nationwide reforms on the number of hours that medical residents can work could cost up to $1.2 billion for hospitals across the country. Study leader Dr. Teryl Nuckols said they also looked at what effects these reforms would have on medical errors.

Nuckols:        If medical errors go down by as little as 3 percent, that could save about $523,000 as well as preventing deaths, which would be great. The problem is the teaching hospitals are very unlikely to save money.

Narrator:       The reforms are designed to reduce medical errors caused by residents being overworked and sleep-deprived, but shorter shifts have their own sets of problems.

Nuckols:        Doing good research on questions like this is challenging because it's real-world types of research. When you're dealing with a hospital with living people and patients and doctors and you make a change like instituting a duty hour limit, there's all kinds of different permutations.

Narrator:       For Science Today, I'm Larissa Branin.