This introductory chapter provides a definition of big data as well as an overview of the use of big data in policing. Big data is a data environment made possible by the mass digitization of information and is associated with the use of advanced analytics, including network analysis and machine learning algorithms. Law enforcement’s adoption of big data is part of a broader shift toward the use of big data and machine-learned decisions throughout the criminal justice system. From surveillance to pretrial determinations and sentencing, big data saturates American criminal justice. It is also the subject of contentious debate in policy, media, legal, regulatory, advocacy, and academic circles. Focusing on the Los Angeles Police Department’s use of big data and associated surveillance technologies, this book studies how big data is actually used by police in practice—and to what consequence.
Introductory Chapter: Machine Learning and Biometrics