Data from the FIM motor scale for patients with spinal cord injury should not be pooled in its raw form, or compared from country to country. Only after fit to the Rasch model and necessary adjustments could such a comparison be made, but with a loss of clinical important items. The FIM cognitive scale works well following rescoring, and data may be pooled, but many patients were at the maximum score.
Lawton, G., Lundgren-Nilsson, A., Biering-Sørensen, F., Tesio, L., Slade, A., Penta, M., Grimby, G., Ring, H., & Tennant, A. (2006). Cross-cultural validity of FIM in spinal cord injury. Spinal Cord, 44(12), 746-752. https://doi.org/10.1038/sj.sc.3101895 (Original work published 2006)