As Denver's Support Team Assisted Response program expands citywide, a new academic study shows sending mental health specialists instead of uniformed police to some low-level 911 calls has made a "dramatic difference" in reducing low-level crime and costs.

Why it matters: The research comes at a time when major cities across the U.S. are looking for ways to divert 911 calls from law enforcement amid continued nationwide scrutiny over racially biased policing and excessive use of force.

• The study provides the most comprehensive analysis available linking a police-alternative program to drops in crime and city spending, according to Thomas Dee, head researcher and professor at the Stanford Graduate School of Education.

Details: Two analysts from Stanford studied the STAR program's six-month pilot, which began in June 2020.

• Over that time, researchers found "robust evidence" that STAR reduced reports of less-serious crimes.

By the numbers: From June to December 2020, the city saw roughly 1,400 fewer reports of low-level criminal offenses, or a 34% decrease, in STAR-patrolled neighborhoods compared to neighborhoods without the program.

• STAR also cost four times less to respond to minor crimes, lowering the average for each offense from $646 to $151.

What they're saying: STAR has shown "extraordinarily promising" results and "provides a rare opportunity for consensus on meaningfully improving public safety and health," Dee said in a statement.

Yes, but: As we've previously reported, some community advocates have raised concerns over the program's direction and control, arguing that the city is making many decisions about its trajectory without public input.

The big picture: Numerous other cities are experimenting with similar 911 reforms, including in New York, San Francisco and Washington, D.C.

• Based on Denver's progress, researchers say there is "credibly causal" evidence that reinventing 911 responses is possible in ways that are radical, sensible and humane.