Work ability and job control Two items from the Work Ability Index (WAI)42 were used to assess employees’ psychological and physical ability to work. These items were: ‘‘How do you rate your current work ability with respect to the physical demands of your work?’’ and ‘‘How do you rate your current work ability with respect to the psychological demands of your work?’’ A 5-point Likert scale was used, with 1=‘‘very poor’’ and 5=‘‘very good.’’