||Ambulatory assessment techniques such as the Experience Sampling Methodology or Ecological Momentary Assessment are increasingly being used in mental health research and in clinical practice. However, many methodological issues remain to be investigated. What is the optimal design for such a study, what would be an optimal questionnaire to use, and how reliable can we apply this methodology in clinical populations? The CCP – together with the research group of Quantitative Psychology and Individual Differences (Faculty of Psychology) – is setting up a series of studies specifically disentangling these issues. The PhD student will take a leading role in these studies.