Intervening with consumers in China to improve choices on private health insurance purchasing

INTERVENTION: A simple randomization method will be used. Firstly, each subject will be assigned a personal ID according to their recruitment order. Secondly, each subject will be given a random number by computer software. Finally, the subjects will be randomly allocated to one of four groups based on the lower quartile, median, and upper quartile of the random numbers. Participants are randomized to four experimental arms: 1. Providing the norm principle to the interviewees, the content of which is "Currently, more than 50% of people in your city have private health insurance." 2. Giving the interviewees the following message: "Not choosing to purchase private health insurance will put you and your family in financial distress when falling ill! Please do not let regret happen!" 3. Giving the interviewees the following message: "Oops! Your benefits are about to expire!" 4. Placebo: without any nudge During the follow‐up period, the researchers will conduct multiple follow‐ups (once every 3 months until 31/12/2025) using online questionnaires to observe the impact of the nudge incentive on the enrollment and awareness rate of the participants. CONDITION: Incentivize participation in private health insurance among the general population in China ; Not Applicable PRIMARY OUTCOME: Private health insurance participation rate is measured using a self‐designed questionnaire every 3 months after the baseline survey and until the end of the follow‐up period in December 2025 SECONDARY OUTCOME: Private health insurance awareness rate is measured using a self‐designed questionnaire every 3 months after the baseline survey and until the end of the follow‐up period in December 2025 INCLUSION CRITERIA: 1. 18 years of age or older 2. Participants in social health insurance 3. Permanently live in Shenzhen, Guangdong, China