Table 2. Names, symbols and definitions of variables.

	Names	Symbols	Definitions
Dependent variable	Internality-stability culture	Cultureis	The rate of the keywords of consistency culture in the sample
	Internality-flexibility culture	Cultureif	The rate of the keywords of involvement culture in the sample
	Externality-stability culture	Culturees	The rate of the keywords of mission culture in the sample
	Externality-flexibility culture	Cultureef	The rate of the keywords of adaptability culture in the sample
Independent variable	The running variable	x i	The week value
	The treatment variable	D	D = 1 if xi≥c or D = 0 if xi<c