How Participants Are Selected in Intelligent Vehicle Human-Machine Interaction Usability Evaluation: A Systematic Review of Current Practices

Participant composition is a critical factor influencing the validity of results in intelligent vehicle human-machine interaction usability evaluation. However, the academic community currently lacks systematic research in this area. Therefore, following the PRISMA guidelines, this study conducted a systematic review of 154 applied research papers. We examined current practices regarding participant sample size, age range, gender ratio, experience background, and recruitment methods. Overall, the findings indicate that the field relies heavily on a “resource-oriented” rather than a “method-oriented” approach, prioritizing convenience and rules of thumb when selecting participants. This reliance leads to methodological flaws that undermine both the external validity and internal validity of evaluation results. This study empirically quantifies the prevalence and manifestations of participant selection bias, thereby providing warnings and practical guidelines to help practitioners implement more scientific evaluations.