Context/Background: process and practice adoption is a key element in modern software process improvement initiatives, and many of them fail. Goal: this paper presents a preliminary version of a usability model for software development process and practice. Method: this model integrates different perspectives, the ISO Standard on Sys- tems and Software Quality Models (ISO 25010) and classic usability literature. For illustrating the feasibility of the model, two experts applied it to Scrum. Results: metrics values were mostly positive and consistent between evaluators. Conclusions: we find the model feasible to use and potentially beneficial.