Dimensions	Factors	Operational definitions (scale item)	References
Organizational characteristics	User involvement	The degree of user's involvement during phases of Information requirements analysis (USER 1); Reviewing consultant's recommendations (USER 2); Project meetings (USER 3); and Decision-making (USER 4)	[45]
	Adequate resources	The resources available for adopting e-signature in terms of usual encouragement (RES 1); Abundant time (RES 2); Abundant funding (RES 3); Abundant human resources (RES 4); and Executive involvement (RES 5)	[42]
	Hospital size	In terms of number of beds (SIZE 1); Number of employees (SIZE 2); and Business volume of a hospital (SIZE 3)	[32]
	Internal need	In terms of reducing paperwork (NEED1); Cutting cost in operations (NEED2); and Offering differentiated service for efficiency (NEED3)	[31]
Environmental characteristics	Vendor support	In terms of quality of technical support (VEND1); Quality of training (VEND2); Adequate technical support during adoption (VEND3); Abundant training (VEND4); and Adequate technical support after adoption (VEND5)	[45]
	Government policy	In terms of setting up HCA (GOV 1); Health insurance IC card (GOV 2); EMR trend (GOV 3); Government's assistance (GOV 4)	[16]
E-signature characteristics	Security protection	Degree of security in terms of security training (SECUR1); Classified management (SECUR2); Security of entity/environment (SECUR3); Access control (SECUR4); Organization of information security (SECUR5); Continuity of operational activity (SECUR6)	[2]
	System complexity	Degree of complexity in terms of work practices in operating the system (SYS1); Complexity in developing the system process (SYS2); Used complexity in integrating the system (SYS3)	[11], [32]