Hey,
For a "meta-analysis" i would like to sum up the result from 6 studies. Still values stated in these studies are median (IQR), mean (SD), mean (range), mean (95% CI). Do I have a chance to calculate a mean +/-SD based on these values?
Thank you for your help in advance!
Kind regards,
Sebastian
I would suggest you:
1. To contact the authors for more accurate information.
2. You can find different methods of approximating the missing piece from each study but then your result's credibility will be diminished.
If you decided to go with # 2 for example when the study reported median and range, you can get approximate estimates of the mean and SD following this paper:
Article Hozo SP, Djulbegovic B, Hozo I. Estimating the mean and vari...
For a given mean and range values, assuming a normal distribution of the data I have also seen this approximation used:
S.D. = ((((100/(Age(max) – Age (min) )*4.54))– (Age(max)– Age(min)))/(1.96*2))
Hello Sebastian,
If you have six independent studies, and each furnishes a sample mean, SD (on a common variable of interest), and sample size (N), then yes, you can certainly combine these to arrive at what might be a better estimate of what the population value might be (if all batches in fact came from the same population).
Attached is a simple worksheet showing the computation of pooled batch estimates of mean and SD based on six independent batches.
Good luck with your work.
Dear David Morse , Thank you very much! Is there a way to conduct similar pooled statistics, if the data i would like to include, are given in different forms:
1) Mean +/- SD
2) Median (IQR)
3) Mean (Range)
4) Mean (95% CI)
Otherwise I will follow Henok G. Woldu advice to contact the authors and see, whether they are so kind to provide mean +/- SD for all values
Thanks for your help!
Hello Sebastian,
No, not unless you are willing to make strong assumptions about data symmetry in each case. Do try contacting authors. I had interpreted your question as meaning that you had all the information, and wanted to combine it.
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