What’s the difference between an informal usability review and an expert usability review?

The fundamental difference between an informal usability review and an expert usability review is the required qualification of the reviewers. An expert review, such as a heuristic evaluation, mandates that the reviewers are specialists in usability, human-computer interaction (HCI), and user experience. These experts use established principles (heuristics) to systematically identify potential usability issues. In contrast, an informal review does not require participants to possess formal usability qualifications. It can be conducted by project team members, stakeholders, or peers to gather quick feedback, making it a less rigorous but often faster evaluation method.

A. An expert review is typically more structured, but the defining characteristic is the reviewer's expertise, not the formality of the process itself.
C. Both review types involve professional judgment, but expert reviews are based on established usability principles (heuristics), not just arbitrary opinion.
D. The number of reviewers is not a distinguishing factor; both review types can be performed by one or more individuals, though multiple are recommended. ---

1. ISTQB® Certified Tester Usability Testing Syllabus (Version 1.0, 2018):

Section 3.2.2.3, Expert review: "An expert review (also known as a heuristic evaluation) is a more formal method of review where a number of usability experts review a user interface to check for problems against a list of recognized usability principles (the “heuristics”)."

Section 3.2.2.2, Informal review: "Reviewers may be colleagues from the same team, from other teams, or anyone from the organization." This section does not specify any required qualifications, contrasting with the "usability experts" required for an expert review.

2. Nielsen, J. (1994). Heuristic evaluation. In J. Nielsen & R. L. Mack (Eds.), Usability Inspection Methods (pp. 25-62). John Wiley & Sons.

Chapter 2, Page 29: Nielsen specifies that for a heuristic evaluation (a type of expert review), "the evaluators should be usability specialists." This foundational text emphasizes that the expertise of the evaluator is a critical component of the method, distinguishing it from reviews conducted by non-specialists.

3. Hartson, H. R., & Pyla, P. S. (2012). The UX Book: Process and Guidelines for Ensuring a Quality User Experience. Morgan Kaufmann.

Chapter 19, Section 19.2.1, "Expert Reviews": The text states, "Expert reviews, also called usability inspections, are a collection of evaluation methods in which an expert in usability and user experience (UX) evaluates a user interface against a set of guidelines or principles." This directly supports that the reviewer's qualification is the key differentiator.