We used mean difference (MD) with 95 % confidence interval (CI), employing a random - effects model for continuous outcomes measured on the same scales. (cochrane.org)
The estimated effects of continuous outcomes are presented as a standardised effect size and dichotomous variables as OR. (jech.bmj.com)
If the same continuous outcome is measured differently across studies, we may calculate an overall standardised mean difference (SMD) and 95 % CI (Deeks 2011). (cochranelibrary-wiley.com)