My meta-analysis was rejected with confusing comments about SMD and Jadad scoring. And how do I switch to SMD or Hedges' g in CMA?

• Absolute mean difference would have been better to assess over SMD
• Jadad scoring is hardly ever used these days. Please consider using the Cochrane risk of bias tool

"Also, when plotting in CMA, how do I set the effect size to SMD or Hedges' g?"

If the journal had asked for a revision, you would simply make the changes. Since it was a rejection, the comments may just be reasons found to justify it. Take what is worth taking, and set aside what does not make sense.

First, an absolute mean difference, or difference in means, is clearer in clinical terms. The effect size even has units, so how effective the treatment is becomes intuitive. But it requires all included studies to use the same, or at least a similar, scale, which you cannot count on. If your studies happen to allow an absolute difference, you can follow the reviewer's suggestion.

The strength of the SMD is that it can combine different scales. Generally, 1.0 is already very effective, and 2.0 is extremely effective, so effective that you may want to check your numbers; it is often a mix-up between SE and SD. In practice, I think both the difference in means and the SMD are good, and Hedges' g is even better.

CMA gives you all of these easily; the software calculates them almost instantly. The one I use most now is Hedges' g. It differs from the SMD in CMA only in statistical detail: Hedges' g has an advantage in small samples, and in large samples they are about the same.

Whichever effect size you want to plot, you can right-click on the effect size and use the two display functions there to switch quickly (as of 2022).

Second, about Jadad. Since 2022, as more researchers around the world have come to understand meta-analysis, Jadad scoring has gone somewhat out of fashion, and the Cochrane RoB 2 tool is well known. Even reviewers who know little about it will often begin by criticizing Jadad as too crude. RoB 2 is designed for randomized trials. If you are submitting to a journal with an impact factor above 4 (as of 2022), you can switch to RoB 2 to give reviewers less to criticize.

Scoring is not hard: find the definitions and signalling questions in the RoB 2 guidance and go through the studies one by one. Each domain ends in one of only three judgments: low risk of bias, some concerns, or high risk of bias. When a judgment is difficult, discuss it with your co-authors and reach a consensus.

Reference

• Higgins JPT, Savović J, Page MJ, Elbers RG, Sterne JAC. Chapter 8: Assessing risk of bias in a randomized trial (last updated October 2019). In: Cochrane Handbook for Systematic Reviews of Interventions, version 6.5. Cochrane, 2024. https://www.cochrane.org/authors/handbooks-and-manuals/handbook/current/chapter-08