Why did US urban homicide spike in 2020? A cross-sectional data analysis for the largest American cities.

Working with data about homicide victims and perpetrators from 50 of America's largest cities, we investigate the explanatory power of some familiar explanations for why murder in those cities rose sharply in 2020. The analysis reveals that the distribution of risk by race was essentially the same in 2020 as in 2019. That empirical finding challenges some theories of how racial tensions after the death of George Floyd may have driven homicide increases. Similarly, homicide growth was not concentrated in those cities with the greatest availability in 2020 of new and older guns, or among the cities that suffered the most from the COVID-19 pandemic. At a minimum, the cross-city outcomes should reduce confidence that some combination of "race, guns, and COVID-19" explains all of the most important aspects of what happened in 2020.