This study explored the factors that influence the perceived complexity of vocational rehabilitation tasks and the abilities of workplace supervisors and rehabilitating employees to carry out rehabilitation in the workplace. The research project was designed to explore whether there was a difference between the perceived complexity of 31 vocationally related rehabilitation tasks as understood by 272 workplace supervisors and 80 employees who were undertaking workplace rehabilitation. By using a probabilistic measurement approach (Rasch model), the study also sought to explore if there was an underlying dimension of the work-related rehabilitation tasks and whether the ability to undertake workplace rehabilitation tasks was influenced by the status and gender of the participants. Additionally, the study sought to assess whether a scale of performance for learning could be constructed, based on the difficulty of the rehabilitation tasks and the self rated capacity of workplace supervisors and their rehabilitating employees. Outcomes of the study suggest that supervisors and rehabilitating employees differ significantly, both in how they view the complexity of vocational rehabilitation and their capacity to participate effectively in workplace rehabilitation. Recommendations are made for designing supervisor rehabilitation training programs in terms of their content and structure, in a bid to make workplace vocational rehabilitation more effective. [Author abstract