The measurement of social support in the European Research on incapaciting diseases and social support:the development of the social support questionnaire for transactions (SSQT)

Social support is supposed to have a beneficial effect on the health and wellbeing of people. It is a central concept in the "European Research on Incapacitating Diseases and Social Support" (EURIDISS). In general, two main distinctions concerning social support are made in the literature, providing four basic dimensions or types of social support: a social-emotional vs an instrumental type og social support, and a 'crisis' or 'problem- oriented' vs 'everyday' or 'daily' type of social support. based on these types of social support , a series of items were formulated to measure actual supportive interactions or exchanges of resources. The items were spread over five scales. The social- emotional type of social support comprised three scales: daily emotional support; problem-oriented emotional support; and social companionship, while the instrumental type of social support consisted of two scales: the daily instrumental support and the problem-oriented instrumental support. Together, these items and scale constitute the so-called 'Social Support Questionnaire for Transactions' (SSQT). The main objective of this paper is to investigate whether one and the same instrument, i.e. the SSQT, allows for meaningful comparisons between patients with rheumatoid arthritis from different countries. More specifically, the dimensionality and invariance of the dimensions across countries of the SSQT are explored. To this end, patients from four differen