RT Journal Article SR Electronic T1 Absolute risk reduction a must JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP 1517 OP 1518 DO 10.1503/cmaj.111-2067 VO 183 IS 13 A1 Robert Y. Shaw YR 2011 UL http://www.cmaj.ca/content/183/13/1517.4.abstract