Study title: Developing conceptual models for navigation, marking, and inspection in the context of 3D image segmentation
On-site interview questions.
Our on-site interviews are formative and will be conducted using a think-aloud protocol. We do not have a list of specific questions, since they will depend on what the user is saying and doing. We provide here a list of the types of questions we will be asking.

Perception/image marking
• Why did you draw that contour?
• What were you trying to delineate?
• What image cues did you use to determine the contour’s location?
• How certain are you about the location of the contour?
• What image features are you looking for?

Sub-task
• What structure are you trying to delineate?
• How would you describe the features of that structure?
• How accurate do you need to be?
• How did you navigate to that structure?
• What view(s) would be helpful to determine if you have successfully segmented the shape?
• What features are important to capture?
• How confident are you that the contour captures the structure?
• How confident are you that the collection of contours is correct?
• What are you doing now?
• How do you convince yourself that the segmentation is correct/complete?

High-level Task
• Describe the high-level features/characteristics of the structure you are delineating.
• Describe its relationship to other structures and the 3D image data
• What instructions would you give a novice user in order to have them understand what they are trying to segment?