On the link between murder rates and violent crime trends: What happens when there isn't one?

Murder rates are up this year in Texas' big cities and across the country, but other (much more common) types of violent crime remain down.

Grits has puzzled over this trend. We usually think of murders as a subset of violent crime - the outliers with worst-case outcomes. Criminologists frequently treat murders as a proxy for other violent crime that may be less well documented. (Rapes or robberies may go unreported, but it's harder to hide dead bodies.) This year, though, those traditional correlations flew out the window. As Jeff Asher and Ben Horvitz wrote in the NY Times this summer:

There have been only four years since 1960 (1993, 2000, 2002 and 2003) when murder increased but overall violent crime decreased nationally, and the increase in murder was small in each of those years. The average absolute difference between the national change in murder and violent crime since 1990 has been just 2.2 percent, so a big increase in murder nationally while violent crime falls is almost unheard-of.

So we're in uncharted territory. If murders go up but other categories of violent crime go down, are we seeing a big-picture trend of more violent crime? Grits has wondered if something else may be happening.

Strangely, police have been solving homicides at ever-lower rates for quite some time now. (Reported the Houston Chronicle, "Homicide detectives [in Houston] solved 89 percent of homicides in 2011. As of May, that number had fallen to 49 percent.") So even if murders were declining before 2020, it wasn't necessarily because the cops did a great job. Moreover, if low clearance rates corresponded to lower murder totals in years past, it's hard to blame the spike this year on police solving fewer crimes.

What else might explain the trend? As hospitals struggle with ICU capacity over COVID, it's possible gunshot victims are losing the competition for resources and dying at higher rates. Earlier this year, a trauma surgeon in Philadelphia identified this tension in a New York Times column, but I haven't seen any follow-up analysis to tell us if that might explain all or part of the rising murder rate. Part of me thinks not. In New York and Chicago, total shooting incidents increased, not just murders. That said, I'm not sure hospitals would admit it if gunshot victims died more often because of ICU shortages.

Regardless, something odd is happening. In a year with so many anomalous occurrences, though, it may be impossible in the near term to figure out just what it is.