Mayor Lenny Curry says crime is “down” in Jacksonville.

Curry’s claim apparently relates to criticism from City Council Member Anna Lopez Brosche, who has filed as a candidate for mayor in the spring elections.

His claim is impossible to fact-check.

If you look at the major crimes (called “index” crimes) reported by the Jacksonville Sheriff’s Office to the FBI over the last 10 years, the index crime rate is down about 34 percent.

But, like a lot of statistics, it depends on the range you choose.

It also depends on whether the cops are reporting honestly or not.

Some jurisdictions have been found fudging the figures in the past.

The FBI makes a point of stating the limitations of its figures in the annual report it publishes, called Uniform Crime Reports.

Crime fluctuates and it usually moves in the same direction in cities throughout the nation. There are times, as when New York City made a major change in tactics, that cities make a demonstrable impact on crime rates.

But what crime experts have said in the past is that the major determinant is the size of the male age 18-25 cohort in the nation. Makes sense. These are the people that do most crimes, and when there are more of them, proportionately, you get more crime.

Another argument tossed around in these political debates is the number of police in a city. I’ve heard it used for at least 50 years but I’ve never seen any definitive evidence that the ratio to police and population has much effect on crime rates.

Here are some other stats that probably will be relevant to the debate:

The police in Jacksonville get about 1.5 million calls from citizens, and dispatch officers about 850,000 times a year. About 100 cops have been added in the past 10 years and the sheriff’s budget is more than $400 million.

The City Council currently is considering crime and public safety to be the No. 1 issue for them to address, so it should be expected that it also will be an issue in the upcoming elections.

But take the claims with a grain of salt. It is true that sheriffs can choose how they report crimes but it is difficult to prove that they are misreporting. The lazy local media certainly are unlikely to take on the task, (unless they take a dislike to the sheriff), so the official numbers posted by the police can be accepted or rejected. It is largely a matter of faith.

Here are the numbers reported, from the Florida Dept. of Law Enforcement Web site: