Table 2.

Control and dependent variables used in experiments 1 and 2.

Variables	Experiment(s)	Measures	Items, n	Sample item	Score range	Cronbach α
Control	1 and 2	Vaccine confidence	3	Overall, I think vaccines are safe.	1=extremely disagree to 5=extremely agree	.85 (experiment 1) and .72 (experiment 2)
Control	2	Propensity to share on social media	3	I share new messages on social media.	1=rarely to 5=always	.72
Dependent	1	Vaccine acceptance	10	Vaccines are effective at preventing diseases.	1=strongly disagree to 7=strongly agree	.76
Dependent	1	Influenza vaccination intention	3	How likely is it that you are going to receive the flu vaccination this winter?	1=extremely unlikely to 5=extremely likely	.82
Dependent	2	Perceived importance of message	3	The message contains crucial knowledge about the vaccine.	1=extremely disagree to 5=extremely agree	.74
Dependent	2	Perceived responsibility for message sharing	6	At this moment, I believe I have the responsibility for sharing this message to improve the influenza vaccination rate.	1=strongly disagree to 7=strongly agree	.89
Dependent	2	Message-sharing willingness	3	I will share this message using different social networking tools.	1=extremely disagree to 5=extremely agree	.72