Table 1.

Questionnaire themes and their operationalization.

Theme	T0/T1a	Items (n)	Topics	Adopted propositions and questions
Participant characteristics	T0	27	(1) General characteristics (eg, gender, date of birth), (2) Use of internet and technology, (3) Informal care, (4) Community involvement and related needs	Examples of questions for topics 2-4: (2) How important is the internet for you to keep in touch with other people? (nominal 5-point scale from “very important” to “unimportant”), (3) Would you accept help from a neighbor? (Yes/No), (4) Do you feel involved with the people living in your immediate vicinity? (nominal 5-point scale: “With almost none,” “With most not,” “With some,” “With most,” “With almost everyone”).
Self-reported use of Grubbenvorst-Online	T0-T1	14-17b	Use of platform in general and of specific functionalitiesc	Examples of questions (nominal 4-point scale: “Never,” “Occasionally,” “Regularly,” and “Daily”): (1) How often do you currently use the Grubbenvorst-Online platform? (T0 + T1); (2) How often do you currently use the “Grubbenvorst Village Calendar”? (T0+T1); (3) Have you used Grubbenvorst-Online less, more often, or to the same extent compared to 4 months ago? (T1)
Expectations of Grubbenvorst-Online	T0	7	Expectations regarding the platform’s added value regarding local participation, informal caregiving, social networking, and feelings of connectedness	Examples of propositions (3-point scale: “[Strongly] Agree,” “Neither agree nor disagree,” “[Strongly] Disagree”): (1) I expect I will partake more in village activities because of Grubbenvorst-Online, (2) I expect that I will use Grubbenvorst-Online to ask my fellow villagers for help (eg, with a job around the house or grocery shopping)
Perceived impact of Grubbenvorst-Online	T1	7	Perceived impact of the platform regarding local participation, informal caregiving, social network, and feelings of connectedness	Examples of propositions (3-point scale: “[Strongly] Agree,” “Neither agree nor disagree,” “[Strongly] Disagree”): (1) Because of Grubbenvorst-Online, I partake more often in village activities. (2) I asked for the help of a fellow villagers via Grubbenvorst-Online (eg, for a job in the house or grocery shopping)

^aT0: baseline questionnaire, T1: questionnaire after 4 months of the study.

^bApart from a few additional questions in T1 (such as example 3), the questions were identical in T0 and T1.

^cNot all functionalities of Grubbenvorst-Online (see Figure 1) were assessed. Only functionalities identified by the initiators as most important were included in the questionnaire.