Assessment of a patient-reported outcome measure in men with prostate cancer who had radical surgery: a Rasch analysis.

Using Rasch analysis as a diagnostic tool, we identified that both the urinary and the sexual function scales have issues that need to be resolved before STAR can be used with confidence in clinical practice. The sexual function scale, in particular, is unlikely to provide precise estimates for the outcomes experienced by men after radical prostatectomy. These results demonstrate the need to evaluate the suitability of any patient-reported outcome measure before implementation in routine clinical practice, preferably using modern psychometric methods.