Table 1.

Variables, indexes, and index descriptions in the model.

Variable, reference, and index description
Altruism—Lin [27]; Kankanhalli et al [25]
	AL1: I like to share my health information with other users on Zhihu.
	AL2: I think sharing health information on Zhihu can help others.
	AL3: I enjoy the process of helping others by sharing health knowledge on Zhihu.
	AL4: In my opinion, sharing health information on Zhihu is a manifestation of one’s social value.
Intrinsic reward—Cho et al [28]; self-design
	IR1: I think by sharing health information on Zhihu, we can gain others’ respect.
	IR2: I think by sharing health information on Zhihu, I can gain praise and recognition from others.
	IR3: In my opinion, sharing health information on Zhihu can help me gain a more positive and confident attitude toward life.
Extrinsic reward—Kankanhalli et al [25]; Cho et al [28]
	ER1: I think sharing health information can result in more followers.
	ER2: I think sharing health information on Zhihu can bring money or other material benefits.
Community influence—self-design
	CI1: I think the Zhihu platform has high credibility in solving health problems.
	CI2: I think Zhihu is an important platform for me to obtain health information.
	CI3: I think the public image of Zhihu can promote users to share health information.
	CI4: I think Zhihu has certain security measures for sharers and the information they share.
	CI5: In my opinion, the platform design of Zhihu (question-and-answer format, agree/disagree mechanism, the like form, and comments) can promote one’s willingness to share health information.
Self-efficacy—Lin [27]; Hsu et al [29]; Chen et al [30]
	SE1: I believe that the health information I have released on Zhihu is scientific and accurate.
	SE2: I can express my opinions on a topic on Zhihu with confidence.
	SE3: I can share new ideas and concepts about health information with others on Zhihu.
	SE4: I can provide rich content in other aspects for a certain health problem on Zhihu.
	SE5: I can accurately address the relevant issues and discuss them on Zhihu.
Willingness to share health information—Schwarzer et al [31]; Bock et al [32]
	WSHI1: I am willing to share the health information I know on Zhihu.
	WSHI2: I would like to continue the practice of sharing health information.
	WSHI3: I will find more effective ways to share health information on Zhihu.
	WSHI4: I would like to participate in the discussion of health information content and express my views.
	WSHI5: I am willing to spend time to improve my knowledge system to provide others with better health information content.