Usability Testing on Tractor’s HMI: A Study Protocol

The success of a human-machine interface (HMI) heavily depends on its usability. An highly usable interface allows the user to more easily achieve his/her goals and in general have a better User eXperience (UX). In work environments, a structured and ready-to-use usability testing protocol can encourage companies to carry out this type of study and focus on UX from the early design phases. Even though numerous methods to test usability exist, industrial companies still have great difficulties to apply them and choose the best ones for the specific purposes. They should be guided into the analysis by a universal step-by-step approach, which helps also not experienced designers selecting the most reliable and useful methods among the available ones. In this direction, the paper proposes a structured protocol to focus on UX and guide companies in testing setup, execution and debriefing in an easy and quick way. Checklists are defined to help during user testing and assure its success. As a consequence, end users can be easily involved to give an added value in design problems identification. The novelty of this paper is the definition of a ready-to-use study protocol that can also be used by non-usability experts, in order to make them familiar with UX analysis and extend this practice also in industrial HMI design. As validation, the proposed protocol was applied to the design of interfaces for agricultural tractors during two different stages of the HMI redesign process.