Only after assistant district attorneys make a preliminary decision about charges would they be permitted to access other information, including race and other demographic details, body camera footage and photos. In each case, regardless of the initial charging determination, all of the evidence will ultimately be reviewed, prosecutors said. If a prosecutor comes to a different conclusion between the first and second steps, that will be recorded and compared to historical data. Prosecutors will also be required to explain what changed their minds, and those patterns will be studied, the office said.

The experiment in blind charging comes as prosecutors’ offices across the nation have been instituting policy changes to grapple with what has been found to be extensive racial bias in the criminal justice system, which has led to disproportionate levels of incarceration among African-Americans.

District attorneys in Brooklyn, Dallas County and elsewhere no longer prosecute low-level marijuana cases. Prosecutors in Philadelphia now handle shoplifting as a minor offense rather than a serious crime if the amount stolen is less than $500. And other district attorneys around the nation have stopped demanding bail for people facing misdemeanor charges.

Legal analysts said the San Francisco policy appears to go a step further by directly confronting ingrained racial bias that leads some prosecutors, for example, to file charges against African-Americans for low-level drug offenses more frequently than against whites, even though studies show that white people use illicit drugs at higher rates.

“It strikes me as an interesting and intriguing thing to do because I don’t get a sense that there’s a lot of systemic change being attempted in this way,” said John Pfaff, a Fordham University law professor and author of “Locked In: The True Causes of Mass Incarceration and How to Achieve Real Reform.”

Mr. Pfaff said the potential for bias might be greater among prosecutors than police officers because prosecutors are more likely to be white than police officers, and are generally from higher than average socio-economic backgrounds.