The Centers for Disease Control and Prevention (CDC) bought access to location data harvested from tens of millions of phones in the United States to perform analysis of compliance with curfews, track patterns of people visiting K-12 schools, and specifically monitor the effectiveness of policy in the Navajo Nation, according to CDC documents obtained by Motherboard. The documents also show that although the CDC used COVID-19 as a reason to buy access to the data more quickly, it intended to use it for more general CDC purposes.