Which is more generalizable, powerful and interpretable in meta-analyses, mean difference or standardized mean difference?

Table 2 “Statistically significant” findings for treatment effect in Cochrane reviews only when I ² of both MD and SMD were less than 30%

	Random-effects model	Fixed-effect model
	N (%)	N (%)
Both significant	164 (45.9)	168 (47.1)
MD significant but SMD non-significant	8 (2.2)	8 (2.2)
MD non-significant but SMD significant	11 (3.1)	9 (2.5)
Both non-significant	174 (48.7)	172 (48.2)

P = 0.647 in random-effects model and P = 1.000 in fixed-effect model, according to the McNemar test.

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