Comprehensive Meta Analysis (CMA)

Pre/post correlations are never reported in a study report. You can calculate them if you have access to the raw data. That usually means contacting the authors. Short of that, if you have done a similar study, you can substitute a correlation calculated from your data. And sometimes, you just have to use an educated guess on the correlation unless you want to exclude the study. When I do guess on a correlation, I do a sensitivity analysis afterwards to determine the effect of altering the correlation on the combined effect size. If the effect is minimal, I don't worry about it. If the effect is large, I would point that out when writing up the systematic review/meta-analysis.

Ma'Mon Abu Hammad

Yes, it is possible to estimate the pre-post correlation coefficient in a meta-analysis using various methods, such as imputing a value or using a range of plausible values. Here are a few options:

Imputing a value: If none of your studies report the pre-post correlation, you can impute a value based on previous research or assumptions. A commonly used estimate is a correlation coefficient of 0.5, which assumes a moderate positive relationship between the pre and post-measures. However, it is important to note that this value may not be appropriate for all studies or research questions.

Using a range of plausible values: Another option is to use a range of plausible correlation coefficients in the analysis, rather than a single value. This can help to account for the uncertainty and variability in the data. A common range is 0 to 0.8, which covers a wide range of possible correlations.

Contacting study authors: If possible, you can try to contact the authors of the included studies to request the missing information or clarification about the pre-post correlation coefficient. This can help to ensure that the analysis is based on accurate and complete data.

Once you have estimated the pre-post correlation coefficient, you can enter it into the appropriate field in the CMA software and proceed with the analysis. It is important to carefully consider the implications of the chosen correlation coefficient and to conduct sensitivity analyses to test the robustness of the results.

How to compare two groups with only two measurements?

Enhanced Yellow Fluorescent Protein (Aequorea victoria) DNA sequence?

What kind of fluid could I use for a pitfall trap that also does not invalidate molecular testing?

What's the best way to measure growth rates in House sparrow chicks from day 2 to day 10?

Do we need to write protocol for a second study of a systematic review that has been registered and published?

How to increase a model accuracy ?

What is the production process of CaFe ferroalloys?

Do I need to do linear regression before running mediation analysis using PROCESS MACRO by Hayes ?

Sample dilution for quantitative analysis using ELISA?

Is There Any Feasible Method To Test Fluorescent Compounds Other Than Fluorescence Spectrometers ??