Author ORCID Identifier

Jonathon Penney: 0000-0001-9570-0146

Document Type

Working Paper

Publication Date



Automated law enforcement systems support privately-operated enforcement bots to take legal action in hundreds of millions of cases a year. In the area of copyright, legal scholars have hypothesized the existence of “chilling effects” that harm public discourse by influencing people to self-censor protected speech. We test this hypothesis in a large-scale quasi-experiment with 9,818 accounts on Twitter that made 5,171,111 tweets. In a confirmatory interrupted time-series analysis, we find evidence that people reduce how much they post online after receiving a take-down notice from a copyright enforcement bot. On average, accounts sent fewer tweets after enforcement (p<0.001). Accounts also changed from a daily increase in public tweets to a decline on average (p<0.001). We also report on novel software that conducts third-party monitoring of the behavioral outcomes of automated law-enforcement systems. Since automated law enforcement can influence public discourse, third-party monitoring like this report will be essential to governing the power of enforcement algorithms in society.


"CC-By Attribution 4.0 International"