An expert review, also called a heuristic evaluation, uses a set of heuristics, or guidelines, to assess the usability of the product. Because the assessment is conducted by usability experts, rather than users, it is commonly called an "expert review."
Expert reviews are sometimes the only UX tool employed at a particular stage of product development. However, they are most effective when paired with usability testing.
The best approach to combining usability testing with expert review is to conduct an expert review first, clean up the interface to the extent possible, then conduct a usability test to combine the findings from experts with the findings from users.
As is frequently the case in using this process, the issues uncovered in an expert review, if addressed before user testing, can eliminate a number of problems users might experience during testing. Once these are eliminated, the user can focus on the potential "show stoppers."
We conduct an expert review by considering first the most appropriate list of heuristics for the product, then conducting an inspection or review with one or more usability experts.
Expert reviews work best when you provides the user profile and scenario of use to us, so that we can walk in the shoes of the user while conducting the inspection.
If more than one usability expert is conducting the review--and we recommend that at least two experts be involved--we each independently review the product, then meet to collate the findings. This is an effective strategy in providing in-depth analysis of the findings, which a single reviewer may have missed.
The report following this meeting identifies the issues and gives each one a severity rating and recommendation for action.
Expert review has the advantage of speed, and it can catch a lot of problems. But users will be the real judge of usability. Combined, these two aspects of a user-centered design process give you two perspectives that work hand in hand.