Figure 2:

Coverage of confidence intervals for β₁ – β₂ estimated from the Riley method with standard variance estimator and the Riley method with robust variance estimator under scenarios 1–9 (denoted as S1–S9) for different settings of within-study correlation (ρ_Wi) and between-study correlation (ρ_B). The between-study variations $\left({\tau }_1^2,{\tau }_2^2\right)$ are set at 0.5, representing a relatively moderate between-study/within-study variation ratio (moderate VR). The red line refers to Riley method with robust variance estimator and the blue line refers to the Riley method with standard variance estimator.