Quality of Life (QoL) research, particularly in healthcare, continues to expand. The final judgment of the impact of a medical treatment is typically made by its ability to positively change the QoL, or at least not to reduce QoL, alongside its treatment i mpact on life expectancy. The nature of QoL and the process of its judgement is only beginning to be understood. Many writers note the lack of conceptual development in QoL. However, this acknowledgment seldom results in concrete proposals to advance the f ield. How people construct assessment about their QoL remains largely unclear. Conceptual ambiguity is illustrated by research findings. Recent research shows that individuals may undergo a shift in expectations, values and views they hold about life (resp onse shift). These may influence the context of their QoL judgment. These challenges need to be understood firstly to comprehensively understand QoL as assessed over time in a medical condition and then to be able to move to developing methods of conceptua lly influencing QoL, rather than seeing it only as a informative outcome variable. The overall aim of this project will be to develop a framework to highlight the possibilities to improve the QoL of individuals in the health setting in Europe. The project aims to understand how the perception of QoL is influenced by response shift, by psychological well-being and heuristics in healthy and diseased populations. The project will contribute to the question concerning the state or trait nature of QoL. Taking he uristics into account, the scientific community will be able to better understand how to assess QoL while controlling for heuristics. This may lead to improved guidelines about questionnaire design. Building on two years of Dr. Hofer¿s experience as a EU M C-Fellow, a number of research objectives will be targeted such as response shift, psychological well-being, heuristics and means to enhance QoL of the individual over this 2.5 year research project.