When the results of large number of quantitative studies are summarised and various analytical tests are conducted to see the effect of any variable, it is termed as meta-analysis. It provides a means through which a large number of quantitative studies of a specific topic could be summarised and studied.  Meta analysis therefore helps in pooling the results from different studies so as to estimate the overall effect by correcting the various sampling and non sampling errors which arises in relation to studies.

Meta analysis basically lies between two types of activities: doing a literature review of current studies in the area of interest and also to conduct a secondary analysis of other researcher’s data. But the technique depends upon the important information available for each of the studies.

As all the information related to methods of study and sample size is not included in published papers, Meta analysis is always not feasible. ‘File drawer problem’ is one problematic area for Meta analysis where research is not generating interesting publishable findings. This trend and tendency creates bias in Meta analytic reviews, as findings that fail to support a hypothesis or are equivocal in their connotations does not hold much chance to be published