In order to give a practical meaning to a concept, it is necessary to measure it. In this chapter, some guidelines for the creation of a life course questionnaire are given, starting from the concept of measurement and all the properties (validity, reliability, responsiveness and interpretability) that an instrument must have, to be defined as a measurement tool. The first step is to define the construct to be measured. Cumulative life course impairment (CLCI) assumes impairment over time of the life course of individuals; key concepts of CLCI are accumulation of risk as well as timing of risk exposure. CLCI is a longitudinal construct, and in order to measure it, it is imperative to take the role of time into account. Questionnaires administered at a certain moment during the patient's life will investigate the impact the disease had on his/her life from the beginning until that moment. Items to be assessed in patients suffering from chronic condition will be, among others, physical and psychological comorbidities, feelings of stigmatization and coping style. Together with the given personality, and other personal and clinical characteristics, they may contribute to changes in the life trajectory compared to a hypothetical 'unaffected average life course'. At the end of the chapter, an example of life course questionnaire is proposed.