Background: Establishing what constitutes clinically significant change is important both for reviewing the function of services and for reflecting on individual clinical practice. A range of methods for assessing change exist, but it remains unclear which are best to use and under which circumstances. Method: This paper reviews four indices of change [difference scores (DS), crossing clinical threshold (CCT), reliable change index (RCI) and added value scores (AVS)] drawing on outcome data for 9764 young people from child and adolescent mental health services across England. Results: Looking at DS, the t-test for time one to time two scores indicated a significant difference between baseline and follow up scores, with a standardised effect size of d = 0.40. AVS analysis resulted in a smaller effect size of 0.12. Analysis of those crossing the clinical threshold showed 21.2% of cases were classified as recovered, while 5.5% were classified as deteriorated. RCI identified 16.5% of cases as showing reliable improvement and 2.3% of cases as showing reliable deterioration. Across RCI and CCT 80.5% of the pairings were exact (i.e., identified in the same category using each method). Conclusions: Findings indicate that the level of agreement across approaches is at least moderate; however, the estimated extent of change varied to some extent based on the index used. Each index may be appropriate for different contexts: CCT and RCI may be best suited to use for individual case review; whereas DS and AVS may be more appropriate for case-mix adjusted national reporting. Key Practitioner Message• There is a potential for different approaches to measuring a change in symptoms over time leading to different conclusions about the effectiveness of services: therefore it is inadvisable to make automatic summative judgements of services based on one approach or metric.• It is important to use the most appropriate method corresponding to the specific question being asked. For example, CCT and RCI at the individual case level to review changes for individual children and families; standardised effect sizes (such as the AVS) to compare populations with a similar case-mix and provide comparisons at the national policy level.• Triangulation with other informationincluding service satisfaction, therapeutic alliance and functioning in everyday lifeis an essential pre-requisite if such data are to be used in meaningful ways.• It is essential that practitioners, service managers, policy makers, commissioners and service users themselves understand the differences in these metrics so that they can appropriately make sense of outcome data presented to them.

Engaging young people in the design and delivery of mental health education could lead to more effective interventions; however, few of these interventions have been evaluated. This study aimed to gain preliminary evidence with regards to the efficacy and acceptability of OpenMinds: a peer-designed and facilitated mental health literacy programme for university and secondary school students. The programme involves a structured programme of education and training for university medical students, who then deliver workshops in secondary schools. Pre- and post-surveys were completed by 234 school students who received two workshops and 40 university medical students who completed the OpenMinds programme and delivered the workshops. The main outcomes in both groups were components of mental health literacy (non-stigmatising attitudes, knowledge, social distance and helping attitudes). Perceived teaching efficacy and interest in mental health careers (university medical students) and workshop acceptability (school students) were also examined. University and school student participation in OpenMinds was associated with significant improvements in three of four mental health literacy elements in both samples. Knowledge and attitudes improved in both samples, social distance improved only in the university sample and knowledge of helping behaviours increased in the school sample. University students' perceived teaching efficacy improved but there was no change in their reported interest in pursuing psychiatry in their career. Acceptability was high; over 70% of the school students agreed that they enjoyed the workshops and liked being taught by a university student. This study provides preliminary evidence for the acceptability and efficacy of OpenMinds as a sustainable peer-led model of mental health education for young people. The OpenMinds programme is ready for efficacy testing in a randomised trial.

-and the CORC central team at the time of writing (including M.W. and I.F): Jenna Jacob, Elisa Napoleone, Victoria Zamperoni, Christa Daboiko, Slavi Savic, and Jeni Page. The authors would like to thank Lisa Arai for her useful comments on an earlier draft.We have no conflicts of interest to declare.