Probation is a sentencing option in criminal court that allows people convicted of crimes the opportunity to remain in the community under court-ordered supervision. California has two types of probation: formal and informal. The major difference between informal and formal probation is how people on probation (called "probationers") are supervised.
People on informal probation (also called "court probation" or "summary probation") aren't supervised by a probation officer. Instead, they report to the court as directed, including when they are:
Informal probation is typically only granted in misdemeanor cases. Because informal probationers don't have probation officers looking over their shoulders, they're less likely to pick up a probation violation than those on formal probation.
People on formal probation are supervised by a probation officer. Reporting requirements vary from once a week to once every month or two, depending on the type of offense involved and the probationer's criminal history. Most probation officers require intensive supervision for "high-risk probationers," such as those convicted of serious or violent felonies or with long criminal records.
Following several years of good behavior, some judges are willing to modify formal probation to informal probation.
Judges often order informal probation in routine misdemeanor cases, like petty theft. But if the judge orders drug testing as a condition of probation in a misdemeanor case, probation will typically be formal—that's so a probation officer can supervise the testing. Probation in felony cases will almost always be formal.