Validity and comparability of studies on the effects of back schools

In this paper, studies on the efficacy of back schools are judged on their methodological quality (internal validity) and mutual comparability (external validity). All available randomised trials (n = 8) were selected for this purpose. The studies were judged on the following criteria: duration and content of the back school programme, selection criteria and number of patients involved, interventions and measures of effect used. With regard to the internal validity of the studies, a number of gaps were found. The numbers of patients involved in the studies were relatively low, no placebo-attention group was used and the principal target of the back schools was not evaluated direcdy. Because of these gaps, it is as yet not possible to formulate a strong and valid judgement on the efficacy of the back schools studied in the trials. In addition to this, the comparability of the studies is rather poor. Taken together, the available studies do not suggest that back schools are particularly effective.