Table 3.

Summary of common errors and confusion related to study messages in initial interview.

Message Group	Response type	Common errors and confusion
Study initiation – description of reward plan	None	- Did not understand how to gain or lose points - Confusion between “points” (e.g. 100) and levels (e.g. bronze, silver) - Thought they needed to respond to the message - Text very long, required scrolling, especially for those with larger font settings
Morning mood questions	Numeric (1-10)	- Flip-flopped scale orientation - Wanted clarification for pain question (i.e. physical vs. mental)
Evening activity questions	Numeric (1-10)	- Did not understand the word “accomplishment”
Evening activity questions	Yes/No	- Variations of yes/no (e.g. “Y,” “N,” “yes, of course”) - Wanted to include information about their planned activity (e.g. “I walked”)
Weekly reward plan updates	None	- Thought they needed to respond to the message
Response reminder	Numeric (1-10), or Yes/No)	- Wanted to respond affirmatively (e.g. “okay”) instead of answering most recent question - Confused about which question to respond to
Error message	Numeric (1-10), or Yes/No)	- Confused by words “value” and “numeric”