In 2004, California voters approved the Mental Health Services Act, a.k.a. Proposition 63, which levied a 1 percent tax on state millionaires to support mental-health programs. Over the last 10 years it has raised more than $13 billion for these programs.

Earlier this year, the Little Hoover Commission, which is a bipartisan board composed of public members appointed by the governor and state Legislature, came out with a report critical of Prop. 63.

In response, former state Senate Pro Tem Darrell Steinberg (an author of Prop. 63) and the California County Behavioral Health Directors Association recently provided data demonstrating the effectiveness of Prop. 63.

While this may have the appearance of a tempest in a teapot, it’s a pretty important teapot, directly impacting millions of Californians suffering from mental illness. What’s more, to quote the Little Hoover report, mental-health professionals everywhere want to know “whether California’s … new prevention-oriented mental health practices are paying dividends.”

So, are they? According to the Little Hoover report, “The results on all fronts, even if actually being accomplished, cannot be convincingly demonstrated.”

Harsh language. Especially considering that, in 2000, a Little Hoover Commission called for major reforms of California’s mental-health system. Prop.63 was designed to accomplish the very things that the previous commission advocated in 2000.

Why is the current Little Hoover Commission so critical of Prop. 63? There are a few reasons:

It clearly would have been better if the provisions of Prop.63 were passed by the Legislature instead of the voters. Among other things, this probably would have prevented us having two oversight bodies, one overseeing previously existing programs and one overseeing Prop. 63 programs.

But it is highly unlikely that taxing the rich to benefit poor, politically powerless, mentally ill people would have ever passed the state Legislature. Therefore, Steinberg and mental-health advocates went directly to the voters through the initiative process. And, remarkably, their initiative passed.

Passed in 2004, when the state was relatively flush, Prop. 63 was designed to bring new resources, especially for prevention and early detection, to the county mental-health programs. But during the recession, mental health and social service programs were slashed.

As a result, existing programs were cut at the same time that new programs were being added. In some years, the state’s reductions and the money added by Prop. 63 were nearly identical. This created fertile ground for disagreement about where Prop. 63 money should be allocated. But without Prop. 63, there would have been no revenue to backfill programs, and many more people would have suffered.

Better data will not eliminate these disagreements about resource allocation. And it’s silly to complain that the goals of Prop.63 have not been fully met without recognizing that the state dramatically decreased mental-health funding during the recession. Nevertheless, the commission does have a point: There should be measurable outcomes.

These measurements were recently provided by Steinberg and the CBHDA.

More than half of Prop. 63 funding goes to “whatever-it-takes” programs providing intensive services for the “homeless and others with the most severe mental illnesses, and urgent care for those with more moderate conditions.”

In a study of the 35,110 people served by county Full Service Partnership programs in 2011-2012, there were dramatic results. Individuals in the programs had a 47 percent decrease in homelessness, a 42 percent decrease in psychiatric hospitalizations, an 82 percent decrease in arrests and a 27 percent decrease in incarcerations. Remarkable.

Twenty percent of Prop. 63 funding goes to prevention and early intervention programs run by the county mental-health directors. Here’s where the data is lacking. It’s difficult to demonstrate that because of early intervention or prevention, something that could have happened did not happen. There are too many uncontrollable variables, and many of the potential benefits are still to come. But we should give county mental-health directors the freedom to run prevention programs in their own counties.

Why? Over the last two years, I have met with dozens of county mental-health directors and their staffs, through the client publications division of the News & Review. The directors are very impressive. Smart, committed public servants, willing to make less money than their colleagues in the private sector. By experimenting and adopting best practices, these directors are developing cost-effective prevention and early detection programs. Each county has different needs and different resources, putting the directors in a far better position than state bureaucrats or the Little Hoover Commission to know what programs will work. We need to give them the chance to do it.

Despite its problems, and despite being implemented during a catastrophic recession, Prop. 63 is an incredible success. With restored funding and additional revenue from the Affordable Care Act, the vision of the Little Hoover Commission in 2000 will be realized. And millions of Californians will benefit.