This study aims to better understand transmission of influenza and other influenza-like illnesses in schoolchildren and their surrounding communities. Specifically, we aimed to describe individual social contacts and respiratory virus transmission to improve parameterization for infectious disease transmission to support the development of disease prevention and control strategies. This includes school-based absenteeism surveillance to determine whether school absence is a predictor of infection with influenza and other respiratory viruses, and extensive characterization of social mixing patterns using wireless sensor devices (motes and contact diaries). Over 2,000 school-children from 8 schools in Pittsburgh, PA participated in SMART in the 2012/2013 school year. We partnered with many of the same schools for the SMART2 study, conducted from 2015-2017.