Many pain scales are used post-operatively in pediatric trials, making the comparison of trials, and the pooling of data for meta-analyses difficult. The Pediatric Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (PedIMMPACT) statement, published in 2008, attempted to address this issue. We aimed to investigate the reasons for authors' choice of pain scales and the potential impact of PedIMMPACT.