Bäuerle, AlexOnzenoodt, Christian vanKinderen, Simon derWestberg, Jimmy JohanssonJönsson, DanielRopinski, TimoBorgo, RitaMarai, G. ElisabetaSchreck, Tobias2022-06-032022-06-0320221467-8659https://doi.org/10.1111/cgf.14536https://diglib.eg.org:443/handle/10.1111/cgf14536We evaluate visualization concepts to represent missing values in parallel coordinates. We focus on the trade-off between the ability to perceive missing values and the concept's impact on common tasks. For this purpose, we identified three missing value representation concepts: removing line segments where values are missing, adding a separate, horizontal axis onto which missing values are projected, and using imputed values as a replacement for missing values. For the missing values axis and imputed values concepts, we additionally add downplay and highlight variations. We performed a crowd-sourced, quantitative user study with 732 participants comparing the concepts and their variations using five real-world datasets. Based on our findings, we provide suggestions regarding which visual encoding to employ depending on the task at focus.Attribution 4.0 International LicenseCCS Concepts: Computing methodologies --> Perception; Human-centered computing --> User studies; Visualization techniquesComputing methodologiesPerceptionHuman centered computingUser studiesVisualization techniques10.1111/cgf.14536235-24612 pages