Quasi-experiments are a valuable source of evidence about effects of interventions, programs and policies: commentary from the Campbell Collaboration Study Design and Bias Assessment Working Group

Affiliations

• ¹ London School of Hygiene and Tropical Medicine, Department of Disease Control, Environmental Health Group, UK. Electronic address: hugh.waddington@lshtm.ac.uk.
• ² Criminology, Law and Society Department, George Mason University, Fairfax, VA, USA.
• ³ School of Public Health and the College of Education & Human Development, Georgia State University, Atlanta, GA, USA.
• ⁴ Modelling, Evidence & Policy Group, Newcastle University, UK.
• ⁵ College of Education, University of Iowa, Iowa City, IA, USA.
• ⁶ Faculty of Medicine, Department of Epidemiology & Community Medicine, Bruyère Research Institute, University of Ottawa, Ottawa, Ontario, Canada.
• ⁷ The Campbell Collaboration, Oslo, Norway.