Crime scene tape blocks the entrance to a house in Gilbert, Ariz., where a multiple slaying occurred last month. (Matt York/Associated Press)

Sean Kennedy is a visiting fellow at the Maryland Public Policy Institute, a conservative think tank. Parker Abt is a student at the University of Pennsylvania.

Last month, the conservative billionaire brothers Charles and David Koch convened their political network to discuss a path forward. Top on the list was criminal-justice reform — a passion the Kochs share with President Obama.

The strange bedfellows, Obama and the Kochs, argue that crime can be tackled even as punishments are reduced, but they are running headlong into Donald Trump’s counternarrative that crime is on the rise and “law and order” must be restored.

Obama and the Kochs insist that crime is actually at all-time lows.

Mark Holden, the Koch brothers’ political adviser, is convinced the evidence backs up his argument, saying: “I don’t think the data shows that [crime is rising]. I think it shows the opposite. I think you’ll see the data shows some spikes in some cities on some issues, but I think we’re much safer, and that’s what the data shows.”

Obama echoed the sentiment in his Democratic National Convention speech last month, when he said, “The crime rate [is] as low as [it’s] been in decades.”

Yet the public is clearly worried about crime, which allows Trump to continue with his “law and order” rhetoric. According to an April 2016 Gallup poll, 53 percent of Americans were concerned “a great deal” about crime and violence — a 15-year high.

So given these opposing claims, what does the data actually show?

The FBI houses a crime clearinghouse called the Uniform Crime Reporting system. More than 18,000 police agencies from across the country self-report based on FBI collection guidelines on every offense known to police, ranging from murder to vandalism, which in turn becomes an annual report called “Crime in the United States.”

A myriad of fact-checkers have relied on this data to “disprove” Trump’s claims on crime.

Many, like Obama and the Kochs, note that from 1960 to 1991 crime rose dramatically in the United States but has since then fallen almost as dramatically through 2014. The consistent drop was impressive, especially in large cities.

There’s one problem, however. Most of those who reject Trump’s crime claims don’t cite any data beyond 2014, the last year of fully available FBI statistics. To any claims that crime has risen since then, they respond that there are only “upticks” in a few cities.

But the FBI reports nationwide data for the first six months of the previous year every January. In January 2016, it reported crime figures for the first half of 2015. That data showed significant increases in violent crime categories. Homicide was up 6.2 percent across the country, while rape was up 9.6 percent.

While the data reported is classified as “preliminary,” the 2015 FBI data is directly drawn from more than 70 percent of participating law-enforcement agencies. It is preliminary only in the sense that it is drawn only from the first half of the year and compared with the first half of the previous year — a statistically valid comparison. Academic research also backs up the FBI’s newest data.

In June, well before Obama’s remarks and most of the fact-checks of Trump’s claims, Richard Rosenfeld of the University of Missouri at St. Louis documented, in a study of 56 major cities conducted for the Justice Department, that homicides were up 17 percent on average. Forty of the cities saw homicides increase, and 12 of those cities saw them increase by more than 50 percent.

Furthermore, data collected by the Major Cities Chiefs Association indicate that this trend has continued into 2016. In the first half of the year, homicides are up 15 percent over 2015. Non-fatal shootings (up 4 percent) and aggravated assaults (3.4 percent) both jumped in the first half of the year as well.

Our own analysis of 20 large cities, gathered directly from publicly available police department data, finds that crime is rising overall, although the increases are spread unevenly across the country.

And compared with 2014 lows, some types of violent crimes are not just rising; they are rising at alarming rates.

For example, since 2014, violent crime is up 47 percent in Los Angeles, 26 percent in Baltimore and 23 percent in Dallas.

In Chicago, arguably the worst-hit city, homicides have risen more than 70 percent since 2014. With almost 400 murders to date, the Windy City is on track to tally more than 650 murders this year alone — the most in almost two decades.

In New York City, homicide jumped almost 6 percent while rape is up 10 percent over the past two years.

It’s true that in some cities, such as Boston and Oakland, homicides and violent crime have continued the long-term downward trend. However, while the rise in homicide rates is not uniform, in aggregate murder is up 21 percent in the major cities we surveyed, comparing the first half of 2014 to the first half of 2016.

Even as robbery dipped slightly, aggravated assault jumped 10 percent. Total violent crime figures for the selected cities rose 6 percent, according to our analysis.

So violent crime, in most major cities at least, is on the rise.

But why? To borrow a line from the band Buffalo Springfield, “There’s something happening here. What it is ain’t exactly clear.” Pundits and criminologists can argue about theories — but neither side is entitled to its own facts on crime.