Better interaction performance attracts more chronic patients? Evidence from an online health platform

•There is coexistence of positive signals and positive externality in online health consultation (OHC) between physician and patient.•A better OHC performance for the physician does not necessarily mean more chronic patients will choose them online.•Interaction depth, which indicates the engagement depth, is negatively related to a patient's choice of a physician.•General health knowledge sharing promotes the positive effect of the interaction breadth on patients’ choices and professional titles can strengthen the positive impact of the interaction length on patients’ choices.•Both general health knowledge sharing and professional title of a physician intensify the interaction depth's negative influence on patients’ choices.