Meta Analysis

Question 1

strength of meta-analysis is that it has high external validity.

Answer 1

E - This is because by combining multiple studies together, the meta-analysis has a very large combined sample. This increases the chance that the sample will be representative, meaning the results are more likely to be generalizable. This gives meta-analysis high external validity.

Question 2

strength of meta-analysis is its internal validity.

Answer 2

E - Because they combine the results of many studies, meta-analyses help counteract problems within an individual study. For example, investigator effects might undermine a single study but would have less impact on an overall result where only a single study within the meta-analysis was undermined by investigator effects.

Question 3

limitation of meta-analyses are their vulnerability to publication bias.

Answer 3

E - Since meta-analyses are studies of published studies, then they only include studies which have been published. A problem here is that researchers are more likely to publish studies that find positive or exciting results, rather studies which don’t find a significant result, or find anything exciting and new (e.g., a replication study). These boring or negative studies may be filed away in a drawer (which is why publication bias is called the ‘file drawer problem)’. Since they are unpublished, they won’t be included in a meta-analysis, meaning the meta-analysis may present a biased overall result.