Table 1.

Description of measures.

Participant Characterization Measures
Measure	Construct	Description	Scoring
TechSAge Background Questionnaire [33] – Modified	General history and demographics	Includes questions related to demographic information, housing and transportation, occupational status, health information, perceptual abilities, and physical mobility.	Mix of multiple-choice, yes/no, and open-ended questions.
Montreal Cognitive Assessment [31]	Cognitive status	Standardized cognitive screening measure used to evaluate global cognitive status. Cognitive functioning assessed across various domains including visuospatial/executive, naming, memory, attention, language, abstraction, and orientation.	Types of responses vary. Scores range from 0 to 30, with higher scores indicating better cognition. Education-adjusted cutoff score for exclusion is < 20.
Geriatric Depression Scale-Short Form [32]	Depressive symptoms	Questions probe for any depressive symptoms the respondent may be experiencing, specifically reflecting over the past week.	Yes/no questions. Scores range from 0 to 15 with higher scores indicating elevated depressive symptoms. Cutoff for exclusion is > 9.
Logical Memory – Delayed Story Recall (Story A) [37]	Episodic memory	Well-established measure to assess memory. Individuals are read a short passage (Anna Thompson story) and asked to recall as many details as possible both immediately and after a delay.	Scores range from 0 to 25 points, with higher scores indicating better verbal episodic memory.
Category Fluency [38]	Language and executive functioning	Participants are asked to recall as many words that belong to a given category (e.g., animals) in 1 min.	Score is the total number of correct words recalled, with higher scores indicating better language/executive skills.

Primary Outcome Measures
Measure	Construct	Description	Scoring
Friendship Scale [40]	Perceived social connectedness	A short scale measuring six dimensions that contribute to social isolation.	5-point Likert scale (0 = not at all, 1 = occasionally, 2 = about half the time, 3 = most of the time, 4 = almost always). Scores range from 0 to 24, with higher scores indicating better social connectedness.
UCLA Loneliness Scale-Version 3 [39]	Subjective feelings of loneliness	Measures how often a person feels disconnected from others.	4-point Likert scale (1 = never, 2 = rarely, 3 = sometimes, 4 = always). Scores range from 20 to 80, with higher scores indicating greater degrees of loneliness.
Quality of Life [41]	Perceived quality of life	Respondents rate the quality of various aspects of their life, including physical health, energy, family, money, and others. This measure was developed specifically for individuals with cognitive impairment. One item pertaining to marriage was removed due to a high number of not-applicable responses.	4-point Likert scale (1 = poor, 2 = fair, 3 = good, 4 = excellent). Total scores range from 13 to 48, with higher scores indicating higher quality of life.

Secondary Outcome Measures
Measure	Construct	Description	Scoring
Lubben Social Network Index [43]	Social network structure	Respondents provide the size of their social networks for family and friends and the frequency of their interactions with them.	Each response is scored from 0 to 5, with total scores ranging from 0 to 30. Higher scores indicate larger and more frequent social network interactions.
Social Activity Frequency (adapted from Refs. [26,44])	Social activity engagement	Respondents rate how often during the past year they have engaged in ninea different activities that involve social interaction.	5-point Likert scale (1 = once a year or less, 2 = several times a year, 3 = several times a month, 4 = several times a week, 5 = every day or almost every day). Scores range from 9 to 45, with higher scores indicating more frequent social participation.

Technology-Based Measures
Measure	Construct	Description	Scoring
Perceived Ease of Use (adapted from Ref. [46])	Ease of use of the OneClick System	Scale to measure ease of use of a system	7-point Likert scale (1 = extremely unlikely, 2 = quite unlikely, 3 = slightly unlikely, 4 = neither, 5 = slightly likely, 6 = quite likely, 7 = extremely likely). Scores are averaged across 6 items, ranging from 1 to 7. Higher scores indicate better ease of use.
Perceived Usefulness (adapted from Ref. [45])	Usefulness of the OneClick System	Scale to measure the usefulness of a system	Uses the same 7-point Likert scale as above. Scores are averaged across 6 items, ranging from 1 to 7. Higher scores indicate better usefulness.
Perceived Enjoyment (adapted from Ref. [47])	Enjoyment of the OneClick System	Scale to measure one's enjoyment of a system	Uses the same 7-point Likert scale as above. Scores are averaged across 4 items, ranging from 1 to 7. Higher scores indicate better ease of use.
Intention to Use (adapted from Ref. [48])	Intention to use the OneClick System	Scale to measure one's intention to adopt a system	Uses the same 7-point Likert scale as above. The score is from one item ranging from 1 to 7. Higher scores indicate a greater likelihood of adoption
System Usability Scale [45]	Usability of the OneClick system	Scale to measure one's perceived usability of a system.	5-point Likert scale (1 = strongly disagree, 2 = disagree, 3 = neutral, 4 = agree, 5 = strongly agree). Scores range from 0 to 100. A score of 68 is considered average.
Computer Proficiency Questionnaire – 12 [49]	Aptitude for using computers	Assesses an individual's experience level with computers as well as how comfortable and successful they feel while using them.	5-point Likert scale (1 = never tried, 2 = not at all, 3 = not very easily, 4 = somewhat easily, 5 = very easily). Total scores range from 6 to 30, with higher scores indicating higher computer proficiency.
Post-Engagement Interview	Opinions regarding OneClick and the social engagement intervention	Locally developed qualitative semi-structured interview	Interviews will be transcribed and analyzed using thematic analysis.

^aThis scale originally included 10 items, but 1 item was dropped due to numerous “Do not wish to respond” answers (see Section 3.2).