In her successful 2010 bid for Sonoma County district attorney, Jill Ravitch hammered two-term incumbent Stephan Passalacqua over a conviction rate she said dropped to second-lowest in the state.

Ravitch vowed to do better, touting two decades of trial experience she said made her better qualified to make decisions and lead an office of about 50 prosecutors.

Voters were persuaded by the tough-talking litigator and elected her by a margin of 54 percent to 46 percent.

But a year into the job, Ravitch is unable to say whether she's winning any more cases than her predecessor.

In response to a request for conviction-rate statistics made earlier this month by The Press Democrat, her office said it did not have the data. The statistics are being collected and will be released at an unspecified date, Ravitch spokeswoman Christine Cook said in a Jan. 17 letter.

<CW-14>During the 2010 campaign, Ravitch challenged the 88 percent conviction rate claimed by Passalacqua for felony cases that went to trial — a small portion of the total cases.</CW>

She cited state Department of Justice statistics from 2003 to 2008 that showed Passalacqua never scored better than 74 percent and had the second-lowest rate in 2007 at just 62 percent, or 20 points below the state average.

She argued Sonoma County deserves better.

"There's a terrible pattern here. You're looking at someone who is consistently receiving a grade of D- or F. We deserve better," Ravitch said during the campaign.

Passalacqua called the state's numbers inaccurate and requested a formal review.

He said his overall conviction rate was 79 percent, a figure he called "outstanding" at a time when county residents supported treatment and jail diversion programs.

Justice officials conceded their numbers could be unreliable, but said they were based on county reporting. Statistics for 2011 were not posted on the state's website.

Legal scholars questioned the difficulty of compiling trial conviction-rate statistics, but cautioned they were only one measure of a prosecutor's performance.

Robert Talbot, professor of law at the University of San Francisco, said they are mostly a political tool. A majority of criminal cases never go to trial, so it's important to consider other factors such as settlements and plea bargains — two things that are hard to quantify.

There are also other variables, like the quality of police investigations and the composition of local juries, he said.

"The conviction rate is an all-important political fact," said Talbot, a former criminal defense lawyer. "But winning or losing might not have much to do with how good a prosecutor you are."