Analyses of a software product line (SPL) typically report variable results
that are annotated with logical expressions indicating the set of product
variants for which the results hold. These expressions can get complicated and
difficult to reason about when the SPL has lots of features and product
variants. Previous work introduced a visualizer that supports filters for
highlighting the analysis results that apply to product variants of interest,
but this work was weakly evaluated. In this paper, we report on a controlled
user study that evaluates the effectiveness of this new visualizer in helping
the user search variable results and compare the results of multiple variants.
Our findings indicate that the use of the new visualizer significantly improves
the correctness and efficiency of the user's work and reduces the user's
cognitive load in working with variable results