Table 2.

Measurement of study variables.

Variable			Description		Measurement
Dependent variable
	Patient satisfaction	Whether the patient expresses appreciation toward the physician		0: The patient does not thank the physician 1: The patient expresses thanks to the physician during the interaction
Independent variable
	Response load	The physician’s average patient receipts per week		ln (the number of patients the physician receives per week divided by the number of days the physician is on duty per week)
	More detailed style	Average word count of the physician’s messages		ln (the total number of words the physician sends in one interaction divided by the total number of messages the physician sends during the interaction)
	Emotional comfort	Whether the physician comforts the patient		0: The physician does not comfort the patient during the interaction
Moderator variable
	Free service	Whether the service is free		0: The patient chooses a paid service 1: The patient chooses a free service
Control variable
	Gender	Patient’s gender		0: Female 1: Male
	Age	Patient’s age		Number of years
	Department	Physician’s department		Category variables for 6 major departments
	Patient residence	Whether the patient lives in Guangdong		0: The patient lives outside Guangdong 1: The patient lives in Guangdong
	Symptom description	Length of the patient’s symptom description		Shown in the patient’s order before the interaction
	Interaction frequency	Total number of exchanges during the chat		Shown in the text data of the physician-patient interaction
	Illness severity	Whether the patient’s illness warrants further treatment and diagnosis offline		0: The physician does not suggest an in-person visit 1: The physician suggests an in-person visit