Empirical Software Engineering 4, 1 (March 1999), 43-69.
HCIL-99-33, CS-TR-4193, UMIACS-TR-2000-72
Inspection is a fundamental means of achieving software usability. Past research showed that the current
usability inspection techniques were rather ineective. We developed perspective-based usability inspection,
which divides the large variety of usability issues along dierent perspectives and focuses each inspection
session on one perspective. We conducted a controlled experiment to study its eectiveness, using a post-
test only control group experimental design, with 24 professionals as subjects. The control group used
heuristic evaluation, which is the most popular technique for usability inspection. The experimental design
and the results are presented, which show that inspectors applying perspective-based inspection not only
found more usability problems related to their assigned perspectives, but also found more overall problems.
Perspective-based inspection was shown to be more eective for the aggregated results of multiple inspectors,
nding about 30% more usability problems for 3 inspectors. A management implication of this study is that
assigning inspectors more specic responsibilities leads to higher performance. Internal and external threats
to validity are discussed to help better interpret the results and to guide future empirical studies.