Fig. 2From: Evaluating the performance of propensity score matching based approaches in individual patient data meta-analysisPercent Mean Bias of the estimated log(OR) by PSM-based approach and heterogeneity in treatment prevalence (left: prevalence varied from 0 to 100%, according to that observed in each study; middle: 50% prevalence; right: 30% prevalence) when the true pooled OR =3Back to article page