Integrating User Interface Design Validation into Human Factors Studies

By Stephanie Larsen

Design validation testing and human factors validation 

Human factors (HF) validation and user interface (UI) design validation are both performed at the end of a product’s development to ensure that the product is suitable for its intended use, users, and use environments, but each with a slightly different scope. Whereas HF validation testing is conducted to generate data related to whether users can interact with the product safely and effectively, UI design validation is conducted to yield evidence that the product meets users’ needs.  

Noting the similarities between HF validation and user interface design validation, manufacturers might wonder how they can combine these activities. Incorporating design validation activities into human factors validation testing can be an excellent use of time and resources. This is especially true when the combined human factors and design validation test sessions are short enough that participants are not fatigued by the session’s end, enabling them to participate fully and generate robust data. Furthermore, combining these activities is useful from a recruiting perspective, noting you can recruit one set of participants for the combined session rather than recruiting one set of participants for each activity.  

User interface design and HF validation integration best practices 

Consider the following best practices to ensure you are integrating user interface design validation elements into HF validation testing is a smooth and productive endeavor: 

• Understand the scope of HF validation and UI design validation activities. For the HF validation test, you will have participants complete use scenarios and knowledge tasks encompassing all critical tasks, and many of these activities will likely be important for user interface design validation as well. Ensure you have a clear understanding of what activities must be performed for the HF validation as well as the UI design validation such that you can determine what additional activities should be added for UI design validation. Furthermore, consider if you need to collect additional data from the HF validation test activities beyond what is traditionally planned (e.g., dominant hand used, glove size, task time).  

• Complete HF validation test activities before user interface design validation questions. Noting the necessary rigor in an HF validation test to avoid bias and represent a realistic interaction, you should not ask any UI design validation questions until you have completed all HF validation test activities. Completing the HF validation test activities would include completing any debrief on use scenarios and knowledge task performance, as well as any further subjective feedback questions. Furthermore, if there are additional hands-on activities required to validate the UI design elements that were not already encompassed within the HF validation test, you should also wait until completing the HF validation test activities to proceed with these UI design validation activities.  

• Write separate protocols and reports for HF validation and UI design validation. Though the HF validation and UI design validation might be happening concurrently, we recommend documenting the test method and results in separate protocols and reports. Writing separate protocols will help to make the distinct method and purpose of each activity clear and will help to maintain the important division between the activities during the design validation planning process. Writing separate reports will also help to maintain the division between the HF validation and user interface design validation, as well as allow each report to focus on its unique objectives.  

Keeping the above recommendations in mind when integrating UI design validation and human factors validation will help yield high-quality data while saving time and resources.

Stephanie Larsen is managing human factors specialist at Emergo by UL.