The goal of this project is to understand the effects of receiving peer information on individuals' conversion rates from brand name prescription medication to generic prescription medication.

At companies where employees are predominantly union members, we will compare the efficacy of a peer information intervention using a testimonial from a union identified employee to an intervention using a testimonial with no union identification, as well as to a no-testimonial intervention.

The control arm will receive a letter signed by our partner company's Chief Medical Officer, explaining the health and monetary benefits of switching from brand name prescription medication to generic prescription medication. The testimonial treatment arm will receive the exact same letter, but the letter will feature an employee's testimonial along with the first name, last initial, city and state of the employee giving the testimonial. The testimonial and union arm will receive the same letter as the testimonial treatment arm but with the addition of the union affiliation of the employee giving the testimonial.

Inclusion Criteria:

• Employee of a company that uses Express Scripts as its pharmacy benefits manager.
• Employee at a company with predominantly union employees.
• Currently taking a brand name medication with an exact generic equivalent.

Exclusion Criteria:

• Employees on any psychological prescription medication.