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Involving patients in the early stages of trial design may be relevant from an ethical point of view, since the patients are those who are most likely to benefit from the research. Also, the quality of the research may benefit from the involvement of patients, who may suggest research questions and outcome measures that are relevant to them, as well as procedures that may lead to better recruitment and retainment. In drug trials, for instance, it may be relevant to ask patients what they expect of a new medication and what they hope the effects are. The instruments used to measure these effects are of pivotal importance for the result of the trial and the subsequent decision-making. In rare diseases the choice of outcomes, and the relative value of several outcomes in a possible composite outcome, is even more important. However, until now there is no standard method to involve patients in the choice and appraisal of outcomes. Therefore, we want to develop a methodology to involve patients in the decisions about relative weights of outcomes in the trial design stage.

Goal Attainment Scaling (GAS)[1] is a technique aimed to measure change induced by treatment. GAS enables patients to set goals and to determine the relative success in achieving these goals on a 5-point scale that is precisely defined beforehand. Since the goals are individually determined, goals may differ in actual content. Its individual and patient oriented approach is one of the appealing aspects of GAS when used as an outcome measure for trials, particularly in orphan diseases. GAS may be more responsive than standardised questionnaires, making it useful in smaller and more heterogeneous samples. In this systematic review, we aim to investigate whether the measurement properties of GAS have been evaluated in drug trials.

At the design stage of a clinical trial, several assumptions have to be made. These usually include guesses about parameters that are not of direct interest but must be accounted for in the analysis of the treatment effect and also in the sample size calculation (nuisance parameters, e.g. the standard deviation or the control group event rate). We conducted a systematic review to investigate the impact of misspecification of nuisance parameters in pediatric randomized controlled trials conducted in intensive care units. We searched MEDLINE through PubMed. We included all publications concerning two-arm RCTs where efficacy assessment was the main objective. We included trials with pharmacological interventions. Only trials with a dichotomous or a continuous outcome were included. This led to the inclusion of 70 articles describing 71 trials. In 49 trial reports a sample size calculation was reported. Relative misspecification could be calculated for 28 trials, 22 with a dichotomous and 6 with a continuous primary outcome. The median [inter-quartile range (IQR)] overestimation was 6.9 [-12.1, 57.8]% for the control group event rate in trials with dichotomous outcomes and -1.5 [-15.3, 5.1]% for the standard deviation in trials with continuous outcomes. Our results show that there is room for improvement in the clear reporting of sample size calculations in pediatric clinical trials conducted in ICUs. Researchers should be aware of the importance of nuisance parameters in study design and in the interpretation of the results.