Standardization of outcome studies in patients with lower urinary tract dysfunction: A report on general principles from the standardisation committee of the international continence society

Scientific evaluation of the outcome of therapeutic interventions in patients is not possible without assessment both before and after the intervention. The methods and measurements used must conform to set criteria in order that they may be applied to all interventions so that comparison between studies may be made. They must be valid, accurate, precise, reliable, and repeatable using a test-retest variation. Evaluations should be properly directed, such that the right variable is measured. Even though methods of intervention and evaluation may vary, certain domains of measurement should be represented and a multidimensional approach undertaken. The time scale for evaluations and interventions and the composition of the study group are important factors, so that some standardization exists, enabling understanding of the results by other investigators and comparison between studies. Unfortunately, no consensus of opinion presently exists on the way in which studies should be performed, including interventions and evaluations, nor on how the results thus obtained should be represented. The scientific basis for many methods is also frequently unclear. A recent American survey of the literature on outcome in genuine stress incontinence classified almost all of the investigations as unsatisfactory and only a few as excellent. We thus have a dilemma between what we ‘‘know’’ as based on reliable scientific data, and what we ‘‘believe’’ based on clinical practice.