1

I am trying to calculate the change in standard deviation for my metaanalysis.

I have the following data available:

  1. mean for control group at baseline and endpoint
  2. mean for intervention group at baseline and endpoint
  3. 95% Confidence interval for control group at baseline and endpoint
  4. 95% Confidence interval for intervention group at baseline and endpoint
  5. Number of subjects in control and intervention group

I would like to calculate the difference in standard deviation for control group (sd_baseline and sd_endpoint) and intervention group (sd_baseline and sd_endpoint). I would like to use the cochrane handbook as reference: https://handbook-5-1.cochrane.org/chapter_16/16_1_3_2_imputing_standard_deviations_for_changes_from_baseline.htm

It is stated that "When there is not enough information available to calculate the standard deviations for the changes, they can be imputed."

Does this mean we need to impute the correlation coefficient for all the studies for every different outcomes separately?

anu
  • 21
  • 1
  • I don't think you're trying to calculate the change in standard deviation. Perhaps the standard deviation of the change? – Jeremy Miles Dec 21 '20 at 17:11
  • But yes, to get that you need to impute the correlation for every outcome. Do don't have CIs or SEs of the difference in the change scores? – Jeremy Miles Dec 21 '20 at 17:12
  • @JeremyMiles When I have 95% Confidence interval for control group at baseline and endpoint, I can calculate the separately the standard deviation for baseline and endpoint. However, when I have these two values, I would like to know how to calculate the delta change in standard deviation (between baseline and endpoint). Do I have to calculate the correlation factor for every parameter across every study? – anu Dec 21 '20 at 17:29
  • Yes. You can't know the CI (or the SE, or whatever) of the difference without knowing the correlation. – Jeremy Miles Dec 21 '20 at 17:42
  • I don't think it's a calculation as much as an estimation. – Jeremy Miles Dec 21 '20 at 17:42

0 Answers0