This is a repository copy of International standards for the analysis of quality-of-life and patient-reported outcome endpoints in cancer randomised controlled trials: recommendations of the SISAQOL Consortium.

Variability indices are a key measure of interest across diverse fields, in and outside psychology. A crucial problem for any research relying on variability measures however is that variability is severely confounded with the mean, especially when measurements are bounded, which is often the case in psychology (e.g., participants are asked "rate how happy you feel now between 0 and 100?"). While a number of solutions to this problem have been proposed, none of these are sufficient or generic. As a result, conclusions on the basis of research relying on variability measures may be unjustified. Here, we introduce a generic solution to this problem by proposing a relative variability index that is not confounded with the mean by taking into account the maximum possible variance given an observed mean. The proposed index is studied theoretically and we offer an analytical solution for the proposed index. Associated software tools (in R and MATLAB) have been developed to compute the relative index for measures of standard deviation, relative range, relative interquartile distance and relative root mean squared successive difference. In five data examples, we show how the relative variability index solves the problem of confound with the mean, and document how the use of the relative variability measure can lead to different conclusions, compared with when conventional variability measures are used. Among others, we show that the variability of negative emotions, a core feature of patients with borderline disorder, may be an effect solely driven by the mean of these negative emotions. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Measures of health-related quality of life (HRQL) and other patient-reported outcomes (PRO) generate important data in cancer randomized controlled trials (RCTs) to assist in evaluating the risks and benefits of cancer therapies, and fostering patient-centered cancer care.However, the various ways these measures are analyzed and interpreted make it difficult to compare results across trials, and hinders the application of research findings to inform publications, product labelling, clinical guidelines and health policy. To address these problems, the Setting International Standards in Analyzing Patient-Reported Outcomes and Quality of Life Endpoints Data (SISAQOL) initiative has been established. This international multidisciplinary consortium, directed by the European Organization for Research and Treatment of Cancer (EORTC), was convened to provide recommendations to standardize the analysis of HRQL and other PRO data in cancer RCTs. This article discusses the reasons why this project was initiated, the rationale for the planned work, and the expected benefits to cancer research, patient/provider decision-making, care delivery, and policymaking.5

This is a repository copy of Prognostic value of patient-reported outcomes from international randomised clinical trials on cancer: a systematic review.

People differ in the extent to which they experience positive (PA) and negative affect (NA) rather independently or as bipolar opposites. Here, we examine the proposition that the nature of the relation between positive and negative affect in a person’s emotional experience is indicative of psychological well-being, in particular the experience of depressive symptoms, typically characterized by diminished positive affect (anhedonia) and increased negative affect (depressed mood). In three experience sampling studies, we examine how positive and negative affective states are related within people’s emotional experience in daily life and how the degree of bipolarity of this relation is associated with depressive symptom severity. In Study 1 and 2, we show both concurrently and longitudinally that a stronger bipolar PA–NA relationship is associated with, and in fact is predicted by, higher depressive symptom severity, even after controlling for mean levels of positive and negative affect. In Study 3, we replicate these findings in a daily diary design, with the two conceptually related main symptoms of depression, sadness, and anhedonia, as specific manifestations of high NA and low PA, respectively. Across studies, additional analyses indicate these results are robust across different time scales and various PA and NA operationalizations and that affective bipolarity shows particular specificity toward depressive symptomatology, in comparison with anxiety symptoms. Together, these findings demonstrate that depressive symptoms involve stronger bipolarity between positive and negative affect, reflecting reduced emotional complexity and flexibility.