Table 5.

Summary of results of robustness analysis

	1. Regression excluding outliers (log)		2. Regression adding group donations and excluding outliers (log)		3. Regression including outliers (log)		4. Regression using two city dummy variables as controls and excluding outliers (log)
	Coefficients	p value	Coefficients	p value	Coefficients	p value	Coefficients	p value
Platform (ref: authorized platform)
WeChat official account	0.52*	0.020	0.75***	0.000	0.85**	0.007	0.71**	0.002
Updates (log)	0.46***	0.000	0.47***	0.000	0.58***	0.000	0.44***	0.000
Award (ref: no)
Yes	0.59**	0.002	0.61**	0.001	0.96**	0.001	0.51**	0.009
Predefined duration (days) (log)	− 0.27***	0.000	− 0.28***	0.000	− 0.36***	0.000	− 0.29***	0.000