Table 1.

Primary outcomes, assessments, and hypotheses.

Primary outcome		Assessment	Hypothesis
Implementation procedures
	Study population	Measured as the total number of participants who were consented and who completed T1a	240 participants
	Participation rate	Measured as the total number of people who agreed to participate in the study divided by the total number of people who were eligible to participate in the study	≥80%
	Number of randomized participants	Measured as the total number of participants randomized	240 participants
	Randomization success	Assessed by comparing intervention and control conditions across all demographic and potential confounding variables at baseline	No differences between intervention and control condition at baseline
	Retention rate for T2b	Measured as the total number of participants who completed T2 divided by the total number of participants enrolled in the study	≥80%
	Retention rate for T3c	Measured as the total number of participants who completed T3 divided by total number of participants enrolled in the study	≥80%
	Retention rate in T2 and T3	Measured as the total number of participants that completed both T2 and T3 surveys divided by the total number of participants enrolled in the study	≥75%
Game demand
	Game download	Assessed on T2 and T3 surveys: did you download the game titled “Singularities”?—Yes; No; Unsure	≥80% selected “Yes”
	Any game play	Assessed on T2 and T3 surveys: did you play the game titled “Singularities”?—Yes; No; Unsure	≥80% selected “Yes”
	Any game play	Total number people who played the game based on game play data from the secure file-transfer-protocol system divided by total number of participants randomized to intervention condition	≥80% played
	Total time of game play	Assessed on T2 and T3 surveys: in the past month, about how long did you play the game “Singularities”?—I did not play the game; Less than 1 hour; 1 hour; 2 hours; 3 hours; 4 hours; 5 hours; 6 hours; 7 hours; 8 hours or more	≥75% selected 1 hour or greater
	Total time of game play	The number of hours the game was played based on game play data from the secure file-transfer-protocol system	≥75% played 1 hour or greater
Game acceptability
	Gaming experience [92]	Assessed on T2 and T3 surveys: response options used a 5-point Likert scale (range: 0-4)—Not at all, Slightly, Moderately, Fairly, Extremely; Question stem was “Please indicate how you felt while playing the game for each of the questions below”; Competence subscale —I felt skillful, I felt competent, I was good at it, I felt successful, I was fast at reaching the game’s targets; Sensory and imaginative immersion subscale —I was interested in the game’s story, it was aesthetically pleasing, I felt imaginative, I felt that I could explore things, I found it impressive, It felt like a rich experience; Flow subscale —I was fully occupied with the game, I forgot everything around me, I lost track of time, I was deeply concentrated in the game, I lost connection with the outside world; Tension and annoyance subscale (reverse coded)—I felt annoyed, I felt irritable, I felt frustrated; Negative affect subscale (reverse coded)—It gave me a bad mood, I thought about other things, I found it tiresome, I felt bored; Positive affect subscale —I felt content, I thought it was fun, I felt happy, I felt good, I enjoyed it	Mean scores ≥2 for each subscale separately
	Desire to play game again	Assessed on T2 and T3 surveys: I would like to play this game again—Strongly Disagree; Disagree; Neutral; Agree; Strongly Agree	≥75% of intervention condition participants selected “Agree” or “Strongly Agree”
	Likelihood to recommend game to friends	Assessed on T2 and T3 surveys: how likely would you be to recommend that your friends play this game?—Definitely; Very Probably; Probably; Possibly; Probably Not; Definitely Not	≥75% of intervention condition participants selected “Definitely,” “Very Probably,” or “Probably”

^aT1: baseline.

^bT2: first follow-up.

^cT3: final follow-up.