This week, Rhode Islanders learned of another medical error when a surgeon at Miriam Hospital put anesthesia in the wrong eye of a patient. But smaller, less dramatic mistakes often go unnoticed and happen even more frequently. Last year, Rhode Island hospitals reported over three hundred mistakes to the department of health. And for every error, there's the trauma that comes with it- for the patient, as well as the doctor involved. In the last of a three-part series, First, Do No Harm, WRNI's health care reporter Megan Hall examines the work of one Massachusetts group whose work begins after a mistake happens.