Although not mandatory, questionnaires might be helpful to assess the presence or severity of ED, especially in those settings where the interviewer is not familiar with the condition and when a measurable clinical response is needed. Although questionnaires are a subjective tool with information from the patient’s interpretation and self-response, it can serve as objective data to assess treatment response or disease progression.

One of the most widely used questionnaires is the International Index of Erectile Function (IIEF); this is a 15-item questionnaire covering five domains including desire, erection, orgasm, ejaculation and satisfaction, with scores ranging from 1 to 5 per question.

A lengthy questionnaire, it is often used in clinical trials, but might be a tedious task during consultation. An abbreviated version of this questionnaire is the IIEF-Erectile Function Domain, one comprised of six questions focused on the erection domain and sexual satisfaction with a maximum score of 30. Men with a normal erectile function will have a score of 25.

Another short questionnaire derived from the IIEF is called the Sexual Health Inventory for Men (SHIM) includes five questions on erectile function related to the prior 6 months, and has a total score ranging from 5 to 25: a score of 22–25 means normal erectile function, 17–21 mild ED, 12–16 mild to moderate ED, 8–11 moderate ED, and <7 severe ED.