Table 1.

Key challenges and implications.

Key Challenges	Implications
Simplicity and ease of use	Barriers to participant recruitment Higher attrition during study Excessive fieldworker time needed
Comfort and stability of fitting	Higher attrition during study Excessive fieldworker time needed Difficulties and delays coding interactions (faces and bodies of participants not in frame if WCs moves from optimal position)
Professional and stylish appearance	Barriers to participant recruitment
Camera field of view and video quality	Difficulties and delays coding interactions (faces and bodies of participants not in frame if WCs moves from optimal position)
Video footage format for synchronisation	Additional steps required processing footage before coding of interaction (e.g. if video stored in segments which need assembling into single sequence)