For years San Francisco has been clocking the average response time to serious crimes at 5.5 minutes, when in fact it takes a median time of 7 minutes from when the 911 call is made for police to arrive on the scene, according to revised calculations just released in a joint Police Department and city controller’s report.

In response to the findings, the SFPD has extended the Priority A response goal for serious crimes to an even longer 8 minutes. There were 80,207 Priority A calls in 2018, representing about a quarter of the 911 calls received.

“In an ideal world, we would be able to respond to every single call as fast as possible. But we had to balance aggressive response times with the actual feasibility of being able to accomplish that goal, given safety concerns and our current resource allocations,” said Alice Kassinger, the lead analyst on the Dec. 3 report.

Hence the more “realistic” response goal of 8 minutes, which at 7 minutes the department is already beating.

Not everyone agrees with the change.

“From the time 911 is dialed, you should have an officer on scene in under 6 minutes,” said Police Officers Association President Tony Montoya.

“Unfortunately, we have a lot of factors, like how fast officers choose to go, the risk of hitting a pedestrian, the potential loss of life, or getting into an accident in such a dense city,” Kassinger said.

And there is the question of whether the city has enough officers to respond faster.

According to the controller’s report, SFPD has approximately 1,850 sworn full-duty officers.

“We need more police officers to support all the needs of our city, including responding to emergency calls,” mayoral spokesman Jeff Cretan said.

“The mayor has pushed to get more officers out on the streets and into the community, and she will continue to work to support our existing officers and fund academy classes so our police have the staffing to respond quickly to every call for service,” Cretan said.

Whatever efforts are taken to adjust response-time expectations or even speed them up, the bottom line is that “the city has grown, but police staffing has not risen, and there are no predictions it will dramatically increase in the future,” Kassinger said.

“It’s a recipe for disaster,” Montoya said.

“The most logical solution is to increase the number of patrol officers at each division. Assigned appropriately, this would reduce the travel time to each respective call,” he continued. “Increasing the number of dispatchers and applying best practices when it comes to technological solutions to reduce time to dispatch an available unit should be considered as well.”

The Police Department declined to say how many officers are on patrol at any given time.

“For safety purposes, we do not provide such information,” police spokesman David Stevenson said. “Police departments around the country face tight competition for new recruits. SFPD is taking proactive steps to further increase recruiting and hiring.”

There are no national standards for measuring police response time. Each city and jurisdiction sets its own criteria, making comparisons difficult.

“Besides FBI-mandated federal crime reporting, most public-safety-related measures vary wildly across the country,” Kassinger said.

For example, in 2018 it took San Francisco police a median time of 1.5 minutes for a dispatcher to get needed information on a Priority A call, about another 48 seconds to dispatch a car, and 4.5 minutes for the car to arrive, for a total of about 7 minutes.

“Drive time is not as important as knowing how long someone will have to wait to see an officer,” Kassinger said.

On this point, the POA agrees.

“Residents deserve the truth as to how long it will take police to arrive and whether or not that amount of time is acceptable,” Montoya said.

The department said it welcomes the report — made at the request of Chief Bill Scott — and that it agrees with the new goal time.

“We evaluate every A priority call we receive with the goal of providing the most expeditious response,” department spokesman Stevenson said. “Again, our response time to a crime scene remains the same.”

“It’s like a student who gets a C on a test being allowed to give themselves an A. Our residents deserve better,” said Montoya.

San Francisco Chronicle columnist Phil Matier appears Sundays and Wednesdays. Matier can be seen on the KGO-TV morning and evening news and can also be heard on KCBS radio Monday through Friday at 7:50 a.m. and 5:50 p.m. Got a tip? Call 415-777-8815, or email pmatier@sfchronicle.com. Twitter: @philmatier