Urinary urgency is a key symptom of overactive bladder syndrome (OAB) and may be more bothersome to a patient than the symptom of urinary frequency. Unfortunately, controversy continues to surround the term 'urgency' and there is no good tool to evaluate the severity of urgency. This fact has constrained the performance of clinical research in this field. The cause of urinary urgency is not fully understood and may vary from patient to patient.