This short technical memo describes the contents of the CHAD-Master database. The database consists of two files, a Questionnaire file that contains demographic and daily variables for each diary-day in CHAD. The corresponding Events file contains the minute-by-minute human activity record (activities and locations) for each diary day. The two files are both indexed by a unique CHADID for each diary-day.
This memo includes a number of tables describing the studies currently included in CHAD-Master, descriptions of all available CHAD-Master variables, an inventory of questionnaire and events variables by study, and definitions for all codes associated with these variables.You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.