A multicenter trial has established the antifracture efficacy of oral daily (2.5mg) as well as intermittent (20mg every other day for 12 doses every 3 mo) ibandronate in women with postmenopausal osteoporosis. As diagnostic spinal radiographs for this trial were read at 2 centers, the study protocol included rigorous procedures for diagnosis of morphometric vertebral fractures. These included standardized qualitative and morphometric assessment methods for diagnosing vertebral osteoporotic fractures and consensus cross-validation procedures for maximizing fracture diagnostic accuracy and consistency between the 2 radiographic reading centers. Using these stringent measures, the between-center discrepancy in the diagnosis of prevalent fractures was only 8%. Furthermore, after cross-validation, discrepancy in the final diagnosis of incident fractures between centers was found for only 4 patients, resulting in a net gain of only 2 fractures in the trial. This meticulous methodology provided a highly effective means of identifying vertebral fractures and recruiting the trial population in which to assess the efficacy of ibandronate in postmenopausal osteoporosis.