The short-term therapeutic effect of 3 techniques of rehabilitation of the lumbar spine (cyphosis gymnastics, kinebalneotherapy and differenciated rehabilitation) was studied out of 87 chronic lumbalgias selected at random and using one of the three techniques administered by 3 physical therapists. A comparison of these 9 couples (technique, technician) was based on criteria evaluated on a blind basis using the traditional unidimensional analysis and also multidimensional analysis. The cyphosis gymnastic reeducation gives less satisfactory results using 26 criteria out of 27. There is an underlying physical therapy factor. A certain number of prognostic factors with implications for any rehabilitation method and for all of the techniques, were disclosed. The comparative testing methods used in the study of drugs are applicable to rehabilitation techniques. However, it was not possible to carry out a comparative study of a reeducation method with a reeducation placebo.