OBJECTIVE: To explore some of the reasons for poor compliance with the use of standardized pain assessment tools in clinical practice, despite numerous guidelines and standards mandating their use.METHODS: First, a review of research and clinical audit literature on the effects of standardized pain assessment tools on patient or process outcomes was conducted, and findings were critiqued. Second, a synthesis of recent literature on the biopsychosocial mechanisms of human detection and recognition of pain in others was presented. Third, the implications for pain assessment in pediatric clinical settings were discussed.RESULTS: There is a lack of good-quality evidence for the efficacy, effectiveness or cost-benefit of standardized pain assessment tools in relation to pediatric patient or process outcomes. Research suggests that there may be greater variability than previously appreciated in the ability and motivation of humans when assessing pain in others. It remains unknown whether pain detection skills or motivation to relieve pain in others can be improved or overcome by standardized methods of pain assessment.DISCUSSION: Further research is needed to understand the intra- and interpersonal dynamics in clinical assessment of pain in children and to test alternative means of achieving diagnosis and treatment of pain. Until this evidence is available, guidelines recommending standardized pain assessment must be clearly labelled as being based on principles or evidence from other fields of practice, and avoid implying that they are ‘evidence based’.