Table 2.

Median (IQR) of heterogeneity metrics for the treatment effect when no effect modification was present^a

τ 2	Prevalence (%)	Number of studies	$I_{\mathrm{two}-\mathit{\text{stage}}}^2$	$R_{\mathrm{two}-\mathit{\text{stage}}}^2$	$I_{\mathrm{one}-\mathit{\text{stage}}}^2$	$R_{\mathrm{two}-\mathit{\text{stage}}}^2$
0.5	30	15	0.10 (0.33)	1.22 (0.80)	0.58 (0.41)	1.75 (1.13)
1.0	30	15	0.44 (0.36)	2.30 (1.76)	0.83 (0.15)	3.29 (2.41)
1.5	30	15	0.58 (0.30)	3.22 (2.53)	0.89 (0.09)	5.84 (4.24)
0.5	70	15	0.01 (0.26)	1.00 (0.65)	0.52 (0.47)	1.76 (1.11)
1.0	70	15	0.39 (0.42)	2.12 (1.69)	0.80 (0.18)	3.33 (2.26)
1.5	70	15	0.55 (0.32)	3.07 (2.67)	0.87 (0.11)	5.66 (4.36)
0.5	30	30	0.12 (0.28)	1.29 (0.72)	0.60 (0.32)	1.79 (0.84)
1.0	30	30	0.47 (0.25)	2.44 (1.29)	0.84 (0.09)	3.49 (1.61)
1.5	30	30	0.62 (0.19)	3.54 (1.98)	0.90 (0.05)	6.32 (3.26)
0.5	70	30	0.06 (0.22)	1.14 (0.57)	0.56 (0.34)	1.81 (0.82)
1.0	70	30	0.42 (0.28)	2.30 (1.30)	0.82 (0.11)	3.52 (1.80)
1.5	70	30	0.59 (0.20)	3.37 (1.93)	0.88 (0.07)	6.36 (3.14)

^aPlease note that I ² is presented here as a proportion varying from 0 to 1, rather than as a percentage