Meta-AnalysisOyunbold Oyunsuren1031310241OutlineWhat is meta-analysis?Advantages and disadvantages of meta-analysisHow to conduct meta-analysis?Some issues in meta-analysisWriting Meta-Analyize report

What is MetaAnalysis?

What is MetaAnalysis?

Advantages and disadvantages of meta-analysisAdvantagesCheaper to conduct researchCan provide strong evidence for hypothesisCan gain data from different types of studiesAn excellent way of reducing the complexity and breadth of researchThis method can be replicated by othersCan determining future researchEasily finding patterns across studiesThe study gathered through this method are objective and any biasness can be easily identified

DisadvantagesPotential for publication bias and skewed dataOne poorly conducted study can place the result of the entire meta-analysis at riskThis method is limited to reviewing only for quantitative researchers.It is quite difficult to find relevant data in this field of study. Requires advanced statistical techniquesNot all studies provide adequate data for inclusion and analysis

How to conduct meta-analysis?

There are several stages to do the meta-analysis:Define the meta-analytic research questionLocate the relevant literatureCalculate effect sizes and code moderating variablesAnalyze the meta-analytic databaseReport and interpret the results

How to conduct meta-analysis?Purpose of this step:Determine what hypotheses your meta-analysis will testEstimate the strength of an effectDetermine moderators of an effectDetermine what types of studies you will include in your analysis

Define the meta-analytic research questionHow to conduct meta-analysis?Goals for this step:Hypotheses should have theoretical valueShould have specific inclusion criteria to make locating studies easierIncluded studies should be appropriate for the hypotheses being tested

Define the meta-analytic research questionHow to conduct meta-analysis?Purpose of this step:Obtain the population of studies related to your research hypothesesModify the hypotheses and inclusion criteria of your analysis to better fit the literatureGoals for this step:Should find every study that has investigated the effect of interestMake your hypotheses better address the questions that researchers have investigated in primary research

Locate the relevant literatureHow to conduct meta-analysis?Purpose of this step:Determine what effects you will examine in each studyCompute a specific estimate of the size of each effectDetermine the value of your moderating variables for each effectGoal of this step:Accurately determine effect size estimates and moderator codesShould try to have estimates for every effect

Calculate effect sizes and code moderating variablesHow to conduct meta-analysis?Purpose of this step:Perform descriptive analyses to determine the overall strength and consistency of the effectPerform moderator analyses to determine if study characteristics influence the effect sizeGoal for this step:Analyses should be validAnalyses should directly answer the research questionsAnalyze the meta-analytic databaseHow to conduct meta-analysis?Purpose of this step:Summarize the results of your analysesRelate your analyses to the research questionsDraw conclusions based on your analyses

Report and interpret the results How to conduct meta-analysis?Goals for this step:Verbally describe the implications of your analysesReport any limitations you see regarding your analysisViolation of assumptionsPowerRepresentativenessSuggest areas of future research

Report and interpret the results Some issues in Meta-Analysis

Writing Meta-Analytic ReportThe easiest way to write up a Meta-analysis is to take advantage of this parallel structure by using the same sections found in primary research. When writing a quantitative literature review you should therefore include sections:Introduction- Methods-Results-Discussion-Writing Meta-Analytic ReportIntroduction-

Writing Meta-Analytic ReportMethod-

To describe how you collected your studies and how you obtained quantitative codes from them To describe how you coded moderator variables To describe how you calculated your effect sizes You should also describe any unusual issues you were forced to deal with during searching, coding, or calculating of your effect sizesWriting Meta-Analytic ReportResult-

To describe distribution of your effect sizes To describe each categorical moderator you want to test To describe each continues variable you want to test To describe the ability of a statistical model to explain your distribution of effect sizes

Writing Meta-Analytic ReportDiscussion-

Web Sources & Book DeCoster, J. (2004) , Meta-analysis Notes, Northwestern Universityhttp://www.dissertation-help.co.uk/dissertation_guide/Meta-analysis-advantages-disadvantages.htm http://onlinelibrary.wiley.com/doi/10.1348/000711010X502733/abstracthttp://journals.lww.com/jhypertension/Abstract/1996/09002/Advantages_and_disadvantages_of_the_meta_analysis.4.aspx http://stats.stackexchange.com/questions/43144/pros-and-cons-of-meta-analyses https://explorable.com/meta-analysis http://www.ncbi.nlm.nih.gov/pubmed/8934372 https://en.wikipedia.org/wiki/Meta-analysis