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systematic reviewshttp://www.thecochranelibrary.com/view/0/AboutCochraneSystematicReviews.html

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A systematic review attempts to identify, appraiseand synthesize all the empirical evidence thatmeets pre-specified eligibility criteria to answer agiven research question. Researchers conductingsystematic reviews use explicit methods aimed atminimizing bias, in order to produce more reliablefindings that can be used to inform decisionmaking.

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PLOSONEhttp://www.plosone.org/static/guidelines#systematic

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PLOSONE

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PLOSONE

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rate

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where

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citations

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diversity or n of subjects

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complexity within studies

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http://www.prisma-statement.org/statement.htmPRISMAA systematic review is a review of a clearlyformulated question that uses systematic andexplicit methods to identify, select, and criticallyappraise relevant research, and to collect andanalyze data from the studies that are includedin the review. Statistical methods (meta-analysis) may or may not be used to analyzeand summarize the results of the includedstudies. Meta-analysis refers to the use ofstatistical techniques in a systematic review tointegrate the results of included studies.

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PRISMAtransparency & replicability

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From: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLoS Med 6(6): e1000097. doi:10.1371/journal.pmed1000097For more information, visit www.prisma-statement.org.PRISMA 2009 Flow DiagramRecords identified throughdatabase searching(n = 380)ScreeningIncludedEligibilityIdentificationAdditional records identifiedthrough other sources(n = 40)Records after duplicates removed(n = 301 )Records screened(n = 301 )Records excluded(n = 153 )Full-text articlesassessed for eligibility(n = 301 )Full-text articlesexcluded, with reasons(n = 153 )Studies included inqualitative synthesis(n = 148 )Studies included inquantitative synthesis(meta-analysis)(n = NA )

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PRISMA 2009 ChecklistSection/topic # Checklist itemReportedon page #TITLETitle 1 Identify the report as a systematic review, meta-analysis, or both. 1ABSTRACTStructured summary 2 Provide a structured summary including, as applicable: background; objectives; data sources; study eligibility criteria,participants, and interventions; study appraisal and synthesis methods; results; limitations; conclusions andimplications of key findings; systematic review registration number.1INTRODUCTIONRationale 3 Describe the rationale for the review in the context of what is already known. 2 – 4Objectives 4 Provide an explicit statement of questions being addressed with reference to participants, interventions, comparisons,outcomes, and study design (PICOS).5 – 6METHODSProtocol and registration 5 Indicate if a review protocol exists, if and where it can be accessed (e.g., Web address), and, if available, provideregistration information including registration number.NAEligibility criteria 6 Specify study characteristics (e.g., PICOS, length of follow-up) and report characteristics (e.g., years considered,language, publication status) used as criteria for eligibility, giving rationale.6Information sources 7 Describe all information sources (e.g., databases with dates of coverage, contact with study authors to identifyadditional studies) in the search and date last searched.5 – 6Search 8 Present full electronic search strategy for at least one database, including any limits used, such that it could berepeated.5Study selection 9 State the process for selecting studies (i.e., screening, eligibility, included in systematic review, and, if applicable,included in the meta-analysis).5Data collection process 10 Describe method of data extraction from reports (e.g., piloted forms, independently, in duplicate) and any processesfor obtaining and confirming data from investigators.5Data items 11 List and define all variables for which data were sought (e.g., PICOS, funding sources) and any assumptions andsimplifications made.5 – 6Risk of bias in individualstudies12 Describe methods used for assessing risk of bias of individual studies (including specification of whether this wasdone at the study or outcome level), and how this information is to be used in any data synthesis.5Summary measures 13 State the principal summary measures (e.g., risk ratio, difference in means). 6Synthesis of results 14 Describe the methods of handling data and combining results of studies, if done, including measures of consistency(e.g., I2) for each meta-analysis.6Page 1 of 2

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initial scopingvariety of terms multiple databases

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develop a search strategywildcardsdo not truncateavoid ambiguitycommon namesdefine inclusion criteriadocument process & double-check

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gaps

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gaps

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gaps

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resourcesch4: Koricheva J, Gurevitch J, Mengersen K (2013) Handbookof meta-analysis in ecology and evolution. Princeton &Oxford: Princeton University Press.