PT - JOURNAL ARTICLE ED - , TI - PURPOSE AND PROCEDURE AID - 10.1136/ebm.6.4.98 DP - 2001 Jul 01 TA - Evidence Based Medicine PG - 98--98 VI - 6 IP - 4 4099 - http://ebm.bmj.com/content/6/4/98.short 4100 - http://ebm.bmj.com/content/6/4/98.full SO - Evid Based Med2001 Jul 01; 6