Antirheumatic therapy has changed from a rather conservative approach towards more aggressive early intervention. Objective measures of the course and outcome of rheumatoid arthritis are essential to understand the disease process and evaluate the therapeutic response. Radiological evaluation fulfils many of the criteria of objectivity: the films provide a permanent record and can be evaluated serially and repeatedly; the changes do not fluctuate with disease activity; and good technique and correct timing can keep the radiation load to a very acceptable level. Consequently, therapies can be evaluated on the basis of their efficacy on radiological progression. In clinical practice, a visual qualitative assessment is usually sufficient, but for therapeutic trials or studies of disease progression in certain patient groups, quantitative methods are needed. A number of different evaluation systems have been introduced, but none of these have gained universal acceptance. No ideal evaluation method (which should be rapid, easy to use and have a good level of reproducibility) has yet been found. Here we make provisional recommendations on the conduct of future therapeutic trials to maximise the likelihood that they will give conclusive results using radiographic outcome assessments.