What are the best practices for testing and validating HMI usability and performance?

1 Define usability goals and metrics

Before you start testing your HMI, you need to define what usability means for your specific context and users. Usability goals and metrics should be based on the tasks, functions, and scenarios that your HMI supports, as well as the expectations and preferences of your operators. For example, you can use metrics such as task completion time, error rate, user satisfaction, and cognitive workload to measure how well your HMI meets your usability goals.

2 Apply user-centered design principles

User-centered design (UCD) is a methodology that involves involving users throughout the design and development process of your HMI. UCD principles can help you create an intuitive, consistent, efficient, and user-friendly HMI. To do so, it’s important to understand your users' needs, characteristics, and context. Involve users in the design, testing, and feedback stages to ensure the HMI meets their expectations. Additionally, use simple and clear language, symbols, and graphics when designing the HMI. Organize and prioritize information and controls in a way that makes them easy to understand. Provide feedback, guidance, and error prevention to make sure users can use the HMI without difficulty. Finally, make sure the HMI is able to adapt to different user roles, levels, and situations.

3 Conduct usability testing with real users

Usability testing is a technique that involves observing and evaluating how real users interact with your HMI in a controlled or realistic environment. This process can help you identify and fix any usability issues, such as navigation problems, layout errors, functionality gaps, or user frustration. You can conduct usability testing at different stages of your HMI development, such as prototyping with a small group of users to get early feedback and validation, pre-deployment with a representative sample of users to verify usability and performance, and post-deployment with actual operators to monitor usability and performance over time and make improvements.

4 Use automation tools and frameworks

Automation tools and frameworks can help streamline and optimize your HMI testing and validation process, allowing you to generate test cases and scenarios based on usability goals and metrics, execute them automatically or semi-automatically, collect and analyze data and results, report outcomes, document recommendations, and integrate test activities with the HMI development lifecycle. Examples of automation tools and frameworks include HMI Testbench (a framework that supports HMI testing and validation based on the ISA-101 standard), Squish (a tool that enables GUI testing and automation for various HMI platforms), and TestComplete (a tool that allows HMI testing and automation across desktop, web, and mobile applications).

5 Follow industry standards and guidelines

Industry standards and guidelines can provide you with best practices, recommendations, and requirements for designing and testing your HMI. Following these standards and guidelines can help you ensure that your HMI meets the expectations and regulations of your industry and domain. For example, ISA-101 defines criteria for the design, implementation, operation, and maintenance of HMI for process automation systems. ISO 9241 specifies the ergonomics of human-system interaction, such as usability, accessibility, and user experience. Additionally, NUREG-0700 provides human factors engineering principles for designing and evaluating HMI for nuclear power plants.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?