The challenge
Deep distrust of the Chicago Police Department and high levels of complaints and force.
The case
From January 2012 to March 2016 the Chicago Police Department assigned 8,480 officers, in a staggered order, to a one-day procedural justice training stressing respect, neutrality, transparency and giving people a voice. A 2020 PNAS study by Wood, Tyler and Papachristos reported that training cut complaints by 10% and use of force by 6.4% over two years, and was widely cited in reform debates. Re-analysis then found a statistical error that inflated the estimates. The corrected work, with Jonathan Roth and Pedro Sant'Anna, found no significant effect on complaints, ruling out cuts larger than 13%, and borderline evidence of a reduction in use of force, with wide uncertainty.
Why the results were mixed
A single day of training is a light dose for changing ingrained police habits, and the correction shows why headline findings need replication before they shape policy.
Sources
- Wood, G., Tyler, T. R., & Papachristos, A. V. (2020). Procedural justice training reduces police use of force and complaints against officers. PNAS 117(18).
- PNAS (2021). Correction to Wood et al. (2020).
- Roth, J., & Sant'Anna, P. H. C. (2023). Efficient estimation for staggered rollout designs. Journal of Political Economy Microeconomics.
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