Measuring stability and change: methodological issues in Quality of Life studies

Studying quality of life needs to take into account particular methodological issues, especially when well-being measurement is aimed at studying stability and change (well-being dynamics). Generally, studies on change and stability may have different objectives, such as (Goldstein, 1979; Menard, 1991): - describing detailed patterns of change, - predicting change values from those obtained in the past, - obtaining insight into underlying causal processes (Engel and Reinecke, 1996). In order to attain these goals, observing and studying changes and dynamics request a coherent methodological approach, including a solid theory of measurement. In particular, they require identification of: • modifiable dimensions (dimensions that may significantly change) • adequate measures (in terms of reliability and validity) • proper analysis approaches (in terms of methods and techniques).