The only real authority of a grand jury is the conducting of an investigation and the issuing of a final report that includes Findings and Recommendations.  The grand jury has no authority to order compliance with any Recommendation, however, the impact of the power of the media and/or public pressure often achieves the desired change.

The preparation and issuing of a final report is a critical step.  Most grand juries use an Editorial Committee to take the draft prepared by the Investigative Committee to put the report in a form that can be understood by the agency to which it is addressed as well as the media and the public.  

Typically, there are about 900 final reports issued each year by California's 58 county grand juries.

To see the impact of Grand Jury reports (and to contribute more examples) see Grand Jury Achievement Report.