When New York City Mayor Michael Bloomberg spots a pothole from the window of his limousine, he does the same thing he would tell any citizen to do: He calls the city's 311 hotline.

The hotline was originally put in place to relieve 911 of non- emergency calls. But Bloomberg, who has called the hotline dozens of times since it went into operation in March, is intent on transforming 311 from a complaint repository to a performance-measurement tool.

Each month, Bloomberg and agency heads are given reports on every complaint logged in the system, from potholes to cell phone dead zones. The reports include crucial information on how long the city has taken to fix each problem. Armed with the data from the report, the mayor can chastise department managers who aren't getting things fixed fast enough. Agency heads can also use the information to set performance goals. Certain problems, such as illegal dumping, are singled out for special scrutiny--the mayor gets a daily report and can track where the sites are and how long it is taking to clean them up.

"It can give us insights on how we allocate resources, how we use resources and how we divide labor," says Jonathan Werbell, a spokesman for the city. "You have to have numbers to hold people accountable."