title: Quasi-experimental study designs series-paper 4: uses and value.
abstract: Quasi-experimental studies are increasingly used to establish causal relationships in epidemiology and health systems research. Quasi-experimental studies offer important opportunities to increase and improve evidence on causal effects: (1) they can generate causal evidence when randomized controlled trials are impossible; (2) they typically generate causal evidence with a high degree of external validity; (3) they avoid the threats to internal validity that arise when participants in nonblinded experiments change their behavior in response to the experimental assignment to either intervention or control arm (such as compensatory rivalry or resentful demoralization); (4) they are often well suited to generate causal evidence on long-term health outcomes of an intervention, as well as nonhealth outcomes such as economic and social consequences; and (5) they can often generate evidence faster and at lower cost than experiments and other intervention studies.
authors.affiliation: Institute of Public Health, Faculty of Medicine, Heidelberg University, Heidelberg, Germany; Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, USA; Africa Health Research Institute, Somkhele, South Africa. Electronic address: tbarnighausen@africacentre.ac.za.
authors.forename: Till
authors.initials: T
authors.lastname: Bärnighausen
authors.affiliation: Department of Medicine, University of Ottawa, Ottawa, Canada.
authors.forename: Peter
authors.initials: P
authors.lastname: Tugwell
authors.affiliation: Department of Health Management and Health Economics, University of Oslo, Oslo, Norway.
authors.forename: John-Arne
authors.initials: JA
authors.lastname: Røttingen
authors.affiliation: Institute of Education, University College London, London, UK.
authors.forename: Ian
authors.initials: I
authors.lastname: Shemilt
authors.affiliation: Center for Global Health and Development, Boston University, Boston, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Rockers
authors.affiliation: Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, USA.
authors.forename: Pascal
authors.initials: P
authors.lastname: Geldsetzer
authors.affiliation: Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, USA; Department of Health Research Methods, Evidence and Impact, Centre for Health Economics and Policy Analysis, McMaster Health Forum, Hamilton, Ontario, Canada; Department of Political Science, McMaster University, Hamilton, Ontario, Canada.
authors.forename: John
authors.initials: J
authors.lastname: Lavis
authors.affiliation: Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Grimshaw
authors.affiliation: Health Systems Research Unit, South African Medical Research Council, Tygerberg, South Africa.
authors.forename: Karen
authors.initials: K
authors.lastname: Daniels
authors.affiliation: Research and Evaluation Strategic Initiative, FHI360, Washington DC, USA.
authors.forename: Annette
authors.initials: A
authors.lastname: Brown
authors.affiliation: School of Public Health, Boston University, Boston, USA.
authors.forename: Jacob
authors.initials: J
authors.lastname: Bor
authors.affiliation: Impact Evaluation, World Bank, Washington DC, USA.
authors.forename: Jeffery
authors.initials: J
authors.lastname: Tanner
authors.affiliation: Department of Information, Evidence and Research, World Health Organization, Geneva, Switzerland.
authors.forename: Arash
authors.initials: A
authors.lastname: Rashidian
authors.affiliation: Instituto de Saúde Coletiva, Federal University of Bahia, Salvador, Brazil; National Institute in Science, Technology and Innovation in Health (CITECS), Salvador, Brazil.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Barreto
authors.affiliation: Department of Economics, University of Göttingen, Göttingen, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Vollmer
authors.affiliation: Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, USA.
authors.forename: Rifat
authors.initials: R
authors.lastname: Atun
mesh_terms: D015984:Causality; D006801:Humans; D065228:Non-Randomized Controlled Trials as Topic; D015203:Reproducibility of Results; D012107:Research Design