Guidelines for Accessible Textual UML Modeling Notations

Textual representations of UML are basic requisites to make UML modeling accessible for visually impaired people. The accessibility, however, varies depending on the concrete realization. Constructing and rating accessible notations is challenging because the notation has to consider requirements of various assistive techniques including screen readers with audio and/or braille output. Neither accessibility metrics for existing textual notations nor comprehensive guidelines for constructing such notations exist. To bridge this gap, we design an interview for rating the accessibility of notations for UML class diagrams and conduct it with six participants for four textual notations. We use the results and related work to derive general design guidelines for accessible textual UML notations. The guidelines allow constructing accessible notations without deep understanding of assistive technologies and can serve as a benchmark for existing notations.