In The Years Since Sandy Hook, Schools Have Ramped Up Their Security

U.S. public schools beefed up security measures with safety drills and parent notification systems in the years surrounding the massacre at Connecticut's Sandy Hook Elementary School, according to a government survey released Thursday.

The uptick came during a four-year span that saw an overall decrease in violent crime reported by schools, but one that included high-profile incidents such as the Newtown, Connecticut, shootings in December 2012 that left 20 children and six educators dead.