Table 4

Areas of methodology improvement in transition intervention evaluation

Area for improvementPossible actionsNeed for additional research
User's involvementActively involving young people and their perspectives in transition's research can help in the ethical design and conduct of research by making it more relevant and beneficial to the patients
Control groups and designUsing randomisation is the most reliable method to ensure a fair comparison between groups. If a conventional parallel group randomised trial is not appropriate, other randomised designs such as cluster randomised trials, stepped wedge designs or preference trials and randomised consent designs should be considered. Studies should respect the concept of equipoise. Thus, it is advisable to propose to the comparison group a control transition procedure based on global recommendations as standard of care. If randomisation is not possible, quasiexperimental or observational designs may be considered but the conditions under which observational methods can yield reliable estimates of effect are limited. Measures to take bias into consideration must be developed.
The use of a mixed-methods design (that includes both quantitative and qualitative approaches) is advocated in the evaluation of complex interventions such as transition programmes.40 Nowadays it concerns only a small number of studies.
Standardise the standard of care to ensure a degree of homogeneity in control groups taking over
Sample size and external validityCalculate a sample size based on realistic and clinically useful assumptions. The estimation of the intervention effect should be relied on the existing literature. To achieve the target sample size and ensure external validity studied interventions should be applicable to young people with various chronic diseases; restrictive inclusion criteria favouring selection of ‘good performers’, should be avoided. The possibility to carry out multicentre studies should be considered.Study the transition-specific adjustment factors that have to be taken into account in the implementation and assessment of multicentre studies
BlindingBlinding of outcome assessors or choice of independent assessors should be considered systematically for appropriate outcomes. The reason for choosing open-label design and its potential effect of assessment bias on the results should be discussed.
Measurement validitySearch of existing validated questionnaires for criteria assessment should be performed before starting the study. Conception and use of new ones for a protocol should be subject to a validation study in parallel. To allow interstudies comparison the assessments by generic and commonly used questionnaires is relevant.41 42Define consensual criteria and methodologies to identify and assess the success of the transition interventions
Validate a generic questionnaire that measures transition satisfaction43
Standardised assessmentResearch on standardisation of outcomes and methods for data collection should be pursued. Outcomes relevant to patients and measures of importance to the health system, including costs must be evaluated, regarding the timing of data collection; evaluation at 36 months after the transfer has to be considered.Develop a methodology to use administrative databases for transition assessments
Interpretation of the effectsRefer to the key elements of the Medical Research Council on developing and evaluating complex interventions, particularly on process evaluation that allows a better understanding of the observed effects.17 44 The effects should be interpreted taking into account not only the theoretical efficacy of the intervention itself but also contextual factors that may affect implementation, intervention mechanisms and outcomes.Identify specific elements of the transition programmes' evaluation that can impact an intervention—apart from the effectiveness of the programme itself—and that should be taken into account when developing the efficacy study and interpreting the results of its evaluation
ReportingTransition interventions should respect the specific set of criteria that has been developed to ensure high-quality reporting of studies.27 28 This allows the good interpretation and replication of complex interventions.