RT Journal Article SR Electronic T1 Rethinking barriers to big data JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP E1 OP E1 DO 10.1503/cmaj.109-4942 VO 187 IS 1 A1 Tim Lougheed YR 2015 UL http://www.cmaj.ca/content/187/1/E1.abstract