Final answer:
A medical assistant should verify a patient's demographic data on each visit to ensure collections control and accuracy in patient records for billing purposes.
Step-by-step explanation:
For effective collections control, it is best practice for a medical assistant to verify the patient's demographic data on each visit. This ensures that the medical office has the most current and accurate information to contact the patient for billing and other communication needs. It helps in reducing the chances of account statements being undeliverable due to outdated address information and can help in prompt payment of bills, thus decreasing accounts becoming delinquent.