VisUnit: Literate Visualisation Studies Assembled from Reusable Test-Suites

We make four contributions to lower the overhead of conducting visualisation user studies and promote the reuse and extension of their materials. (i) A declarative Javascript specification lets experimenters describe how studies are assembled from tested visualisations, datasets, tasks and chosen evaluation strategies. (ii) A VisUnit library translates these into sequences of visual stimuli and delivers them to participants. We move away from monolithic evaluation stimuli typical of previous work and construct studies around three ingredients – visual encodings, datasets, and tasks – that can be developed independently and recombined flexibly. (iii) This paves the way for developing benchmark data+tasks test-suites as independent, reusable resources to support multiple studies. (iv) Structuring user studies as “literate” visualisation notebooks brings together in the open all ingredients necessary for replication and scrutiny: formal design specification; underlying materials; participant-facing views; and narratives justifying design and supporting reuse.