The preventive services included in our analysis were selected from multiple sources, including a previous paper that examined out-of-pocket costs for preventive care, along with updated guidelines from the USPSTF and HRSA. Our analysis included some covered prescription drugs, including contraceptives and PrEP, that were not included in the paper. We used the same broad 'All preventive services' methodology outlined in the paper to identify claims for preventive services. We included claims that occurred in an outpatient or office setting and did not restrict claims to the first occurrence of the service per person per year. For contraceptive services, we included claims that had either a procedure code or diagnosis code from the list. For breast cancer screening and tobacco counseling, we included claims that had a procedure code from the list. For all other services we required claims to have both a diagnosis code and procedure code from the list. We restricted claims for some service categories by age and sex based on USPSTF, HRSA and ACIP guidelines, as shown in the table below:

We excluded claims for enrollees who were not enrolled in an ESI plan or did not have prescription drug coverage at the time of service. We also excluded claims where the ESI health plan was not the primary payer (e.g. claims covered by workers' compensation).

Average prices were calculated by dividing the total spending for each procedure code or standardized 30-day supply of medication (NDC code) and dividing by the service count (for procedure codes: count of distinct patient ID and service date combinations; for NDC codes: count of 30-day standardized fills). Note that average price calculations at the procedure level only include costs for the individual procedure code, and not related ancillary services (e.g., labs, anesthesia, etc.).