The project consists of the preparation and implementation of a validation field test aimed at calibrating the Dutch and French language versions of the “Work Disability- Functional Assessment Battery” (WD-FAB). The WD-FAB will be validated by means of expert and focus groups with end users. Based upon statistical analyses on data collected during field testing the item bank will be calibrated for Computer Adaptive Testing, and an e-health application will be developed and made available for use by the Belgian social security institutions.