• You can't always tell if the doctor doing a procedure was adequately trained to do it. For instance, a doctor may learn to do cosmetic laser treatments at a weekend retreat.

• And you can't find out about doctors who have not been investigated or have been investigated but never disciplined. Malpractice attorney Eric Nielson complains about a doctor he calls "one of the most incompetent doctors I've ever run into" but has no black marks against him from DOPL.

The many things you can't find out make it difficult to assess how well you're protected by the regulatory bodies and the health-care system that you probably assume keeps you safe. The things you can't find out make it difficult to know if that doctor whose name you see in the Yellow Pages is the doctor you want to trust your skin or feet or life to.

At the same time, the things you can find out about your doctor — the fact that he has been put on probation, for example — may not mean he's a doctor you should avoid. There are degrees of culpability and potential harm to patients (a doctor might be in trouble because his secretary forged a prescription, or he might be injecting the drugs himself; he might have kept sloppy records or negligently killed a patient), and a doctor with a history of misconduct may have been rehabilitated.

The circumstances that led to discipline in the first place may even have been stacked against him. There is a Utah doctor, for example, who had sleep apnea but was misdiagnosed, prescribed Ritalin and became addicted. Now his medical license is restricted, and he's trying to get his life back together.

In researching this story, reporters attended licensing board meetings and consulted patients, doctors, malpractice attorneys and five years' worth of the quarterly online newsletters that DOPL publishes about disciplined health practitioners. This story includes names of some who illustrate gaps in what patients can know about their doctors, but readers should not assume those named here are "bad" doctors or that the doctors not named here are "good."

Doctors named in this story have been given a chance to tell their story. Many accepted. Periodontist McCombs was among those who chose not to respond on the record.

The government checks up on restaurants, dropping in to see if the cooks are washing their hands, and it periodically keeps tabs on meat-packing plants and grocery deli departments. But the state doesn't do random checks on doctors' offices. DOPL doesn't have enough staff or funding to do that, and it's doubtful such monitoring would help — DOPL would have to be lucky enough, to use one real example, to show up just when a doctor was stealing Lortab from a co-worker's purse.