Using natural experiments to evaluate population health interventions: new Medical Research Council guidance
Peter Craig, Cyrus Cooper, David Gunnell, Sally Haw, Kenny Lawson, Sally Macintyre, David Ogilvie, Mark Petticrew, Barney Reeves, Matt Sutton, Simon Thompson
J Epidemiol Community Health Dec 2012, 66 (12) 1182-1186; DOI: 10.1136/jech-2011-200375