Comparative usability evaluation

Abstract

Em irical usability evaluations (particularly forrna~ive J ev uations [13]) hinge on observing and interpreting critical incidents [8] of use. We proposed [3,5] augmenting critical incident methods by analysis of what we called critical threads: sets of causally related user episodes that, taken together, define major usability themes. This paper extents this work to the comparative usability analysis of a related artifact. We discuss how our earlier claims analysis was used to orient and simplify our current evaluation efforts.