California officials say that a law to reform the state's workers' compensation system by introducing evidence-based treatment guidelines has paid major dividends since its implementation three and a half years ago.

A report released by the state Department of Industrial Relations says that the state has saved $600 million more than initially projected.

The state attributes much of the savings to a new approach to treatment for workers who are injured on the job. Concerns about the over-prescribing of opioids to injured employees prompted the state to devise stricter guidelines for treating certain conditions. The state also created an independent board to hear and resolve disputes over treatment and is in the process of creating a standard drug formulary.