title: Quasi-experimental study designs series-paper 8: identifying quasi-experimental studies to inform systematic reviews.
abstract: OBJECTIVE
  This article reviews the available evidence and guidance on methods to identify reports of quasi-experimental (QE) studies to inform systematic reviews of health care, public health, international development, education, crime and justice, and social welfare.
  
  
  METHODS
  Research, guidance, and examples of search strategies were identified by searching a range of databases, key guidance documents, selected reviews, conference proceedings, and personal communication. Current practice and research evidence were summarized.
  
  
  RESULTS
  Four thousand nine hundred twenty-four records were retrieved by database searches, and additional documents were obtained by other searches. QE studies are challenging to identify efficiently because they have no standardized nomenclature and may be indexed in various ways. Reliable search filters are not available. There is a lack of specific resources devoted to collecting QE studies and little evidence on where best to search.
  
  
  CONCLUSIONS
  Searches to identify QE studies should search a range of resources and, until indexing improves, use strategies that focus on the topic rather than the study design. Better definitions, better indexing in databases, prospective registers, and reporting guidance are required to improve the retrieval of QE studies and promote systematic reviews of what works based on the evidence from such studies.
authors.affiliation: York Health Economics Consortium, Enterprise House, Innovation Way, University of York, York YO10 5NQ, UK. Electronic address: julie.glanville@york.ac.uk.
authors.forename: Julie
authors.initials: J
authors.lastname: Glanville
authors.affiliation: 3ie, London, UK.
authors.forename: John
authors.initials: J
authors.lastname: Eyers
authors.affiliation: Department of Economics, University of York, York, UK.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Jones
authors.affiliation: EPPI-Centre, 10 Woburn Square, London WC1H 0NR, UK.
authors.forename: Ian
authors.initials: I
authors.lastname: Shemilt
authors.affiliation: American Institutes for Research, San Mateo, CA 94403, USA.
authors.forename: Grace
authors.initials: G
authors.lastname: Wang
authors.affiliation: Cochrane Effective Practice and Organisation of Care Group, Norwegian Satellite, Norwegian Knowledge Centre for the Health Services, Oslo, Norway.
authors.forename: Marit
authors.initials: M
authors.lastname: Johansen
authors.affiliation: Eccles Health Science Library, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Michelle
authors.initials: M
authors.lastname: Fiander
authors.affiliation: Baruch College-City University of New York, New York, New York, USA.
authors.forename: Hannah
authors.initials: H
authors.lastname: Rothstein
mesh_terms: D017408:Guidelines as Topic; D006801:Humans; D065228:Non-Randomized Controlled Trials as Topic; D012107:Research Design; D012196:Review Literature as Topic
keywords: Databases; Information retrieval; Quasi-experimental studies; Search strategies; Study identification; Systematic reviews