Defining Success A minimum of one hour of daily hearing aid use reported on the International Outcome Inventory – Hearing Aids. “Think about how much you used your present hearing aid(s) over the past two weeks. On an average day, how many hours did you use the hearing aid(s)?” Response options: none, <1 hour/day, 1-4 hours/day, 4-8 hours/day, 8+ hours/day AND At least moderate benefit from hearing aids reported on the International Outcome Inventory – Hearing Aids. “Think about the situation where you most wanted to hear better, before you got your present hearing aid(s). Over the past two weeks, how much has the hearing aid helped in those situations?” Response options: not at all, slightly, moderately, quite a lot, very much So people have to respond with any of the ‘bolded’ response choices to be categorized as successful.