Background <p>Workplace-based learning in surgery has developed an inherent focus on competency-based assessment tools and quantifiable skills. Trust is an essential element in the framework of Entrustable Professional Activities (EPA). However, trust is difficult to quantify and assess. Procedural variation seen among residents may be influenced by supervisors’ trust in their trainee. The objective of this study was to explore how supervisors base their trust decisions when granting autonomy to surgical residents.</p> Methods <p>A constructivist grounded theory approach was used to guide interviews with specialists in general surgery at different teaching hospitals in Denmark.</p> Results <p>We recruited and interviewed 19 surgeons, all of whom were specialised within general surgery. In the interviews, the informants articulated four interconnected themes that characterise the elements that supervisors employ when making trust decisions about when to grant autonomy to surgical residents: (1) approach, (2) relational skills and competencies, (3) departmental solidarity, and (4) technical skills and knowing own limits. On the basis of these four categories, we created the acronym ARTS.</p> Conclusion <p>ARTS may provide a point of departure for critical discourse on the criteria that should inform decisions regarding the granting of autonomy, as well as the essential components that ought to be integrated into assessment frameworks.</p>