Building a product based on the assumptions of the designer can sometimes work great. But, even experienced UX designers can make errors, biased or there are situation where the designer itself may get surprised by the results.
To eliminate these risks Usability studies are done. User testing can seem like a time consuming task and there maybe times where the designer may be very certain and predict the outcomes. But usability testing helps in finding the designs that do or do not work.
Hoa Loranger’s article says Why usability Studies when you know the answer?
Build Camaraderie and Trust:
When the team is involved in the usability testing they get a first hand experience of what users thinks. And the shared learning experience will give them a trust and what the end user thinks are more important.
Bridge Divergent Ideas:
When there are more divergent ideas, user testing may help in identifying the elements that works best and it can be used to do further ideations.
Manage Awkward Requests:
User testing data may work well when there are awkward requests rather than using simple words to say no.
Avoid Delivering the Bad News Yourself:
Usability testing will let the customers deliver the bad news when there is a terrible idea proposed.
Just in Case You’re Wrong:
There is a slight chance that the designer’s decision could be biased or wrong, which maybe found with user testing.
Via: NN Group