Meta-analysis is research on specific topics. Where it is possible to do analyses of a collection of research results, there is scope for meta-analysis. Meta-analysis of the effectiveness of corrections and meta-analysis of the effects of divorce on children. Meta-analysis is a method for amalgamating, summarising, and reviewing previous quantitative research. Using meta-analysis, a variety of questions can be investigated based on existing body of primary research studies. Selected parts of the reported results of primary studies are entered into a database, and this "meta-data" is "meta-analyzed", in similar ways to working with other data, descriptively and then inferentially to test certain hypotheses.
As with any research technique, meta-analysis has its advantages and disadvantages. Meta-analysis provides a systematic overview of quantitative research which has examined a particular question. The appeal of meta analysis is that it in effect combines all the research on one topic into one large study with many participants. The danger is that in amalgamating a large set of different studies the construct definitions can become imprecise and the results difficult to interpret meaningfully.
Meta-analysis has been used to give helpful insight into the overall effectiveness of interventions, the relative impact of independent variable, and the strength of relationship between variables. Meta analysis can be used as a guide to answer the question 'does what we are doing make a difference to X?', even if 'X' has been measured using different instruments across a range of different people.
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