31 May 2020
The study is preliminary, and the author is very clear on this, but the results are striking.
Police unionization has increased pay and benefits, no big surprise there, and a slight decline in police employment, which might correlate with the increase in the cost, which is also not a surprise.
The big take away is that there is a substantial increase in the lethality of law enforcement, with the death toll of minorities accounting for the bulk of the increase.
The number (admittedly preliminary) is stunning, "We find a substantial increase in police killings of civilians over the medium to long run (likely after unions are established) with an additional 0.026 to 0.029 civilians killed in a county each year of whom the overwhelming majority are non-white."
Given that there are (Googling furiously) 3,143 county equivalents in the United States, this means that we would see about 82 extra deaths a year, and over the past 40 years, this would be more than 3200 excess deaths.
The obvious conclusion is that the decrease in accountability of police officers has resulted in increased violence and police racism, though as is frequently stated, correlation is not causation.
Additionally, court rulings over the past 50+ years have had the effect of reducing police accountability for the use of force as well, so teasing out the effects specific reductions of accountability would be difficult.
The obvious take-away though is that we need greater accountability for our police forces.