PURPOSE: We established severity banding ranges, bother assessment and key item content in principal patient reported outcomes measures in men seeking therapy for lower urinary tract symptoms. MATERIALS AND METHODS: Data for International Prostate Symptom Score (I-PSS) and International Consultation on Incontinence Questionnaire Male Lower Urinary Tract Symptoms (ICIQ-MLUTS) were derived from a study evaluating 820 men at 26 United Kingdom hospitals. ROC curves were used to establish severity bandings. RESULTS: Classification tree showed that thresholds between mild-moderate and moderate-severe severity bands were 15 and 27 for I-PSS, 16 and 26 for ICIQ-MLUTS/severity, and 22 and 81 for ICIQ-MLUTS/bother, respectively. Highest area under the ROC curve and lowest Akaike's information criteria of univariate logistic regression indicated that ICIQ-MLUTS/bother was more related to global quality of life than were I-PSS and ICIQ-MLUTS/severity. The symptoms affecting I-PSS-quality of life (QoL) were only fully identified by ICIQ-MLUTS, because 2 key symptoms (urinary incontinence and post-micturition dribble) are not measured by I-PSS. ICIQ-MLUTS demonstrated that bother of some lower urinary tract symptoms is disproportionate to severity, and that persisting high bother levels following surgery are more likely due to storage (18% to 25%) and post-voiding (18% to 28%) lower urinary tract symptoms than voiding lower urinary tract symptoms (5% to 13%). Symptom improvement after surgery was uncertain if baseline I-PSS-QoL score was less than 3. CONCLUSIONS: The severity threshold scores were measured for the 2 key lower urinary tract symptoms patient reported outcomes measures, and the results indicate suitable categories of symptom severity for use in men referred for urological care. The ICIQ-MLUTS measures all the lower urinary tract symptoms affecting quality of life and includes individual symptom bother scores.