Table 4.

Aggregated user responses to open-ended questions.

Category and response			Value, n (%)
Best part of MyCOVIDKey
	Total responses	18 (100)
	Useful tool, good for contact tracing	6 (33)
	Accessible/good locations for barcodes	3 (17)
	Easy to use/simple	3 (17)
	Tracks statistics/game-like	2 (11)
	Minimal time required	2 (11)
	Scanning worked well	2 (11)
	Self-assessments	2 (11)
	Gift card incentives	1 (6)
Worst part of MyCOVIDKey
	Total responses	19 (100)
	Web browser	10 (53)
	Key-in did not always work as expected	6 (32)
	Difficult to use when carrying things	3 (16)
	Automatic logout	3 (16)
	Effort required	2 (11)
	Unsure who sees information	1 (5)
	Frequent self-assessments	1 (5)
	Number of steps to get to key-in window	1 (5)
	Unclear instructions	1 (5)
	Unsure if others are using frequently/effectively?	1 (5)
	Expectation of receiving notification if someone tested positive for SARS-CoV-2	1 (5)
Ways to improve MyCOVIDKey
	Total responses	20 (100)
	Make it a native app	12 (60)
	Open directly to scanner, faster scanning	4 (20)
	Integration with other location services, self-report locations visited	4 (20)
	Offline mode	2 (10)
	More key-in locations	2 (10)
	More transparency on how information is collected and shared	1 (5)
	Clearer instructions for use	1 (5)
	More use statistics	1 (5)
	Option to self-report positive test result	1 (5)