On 03/19/15, 03/26/15, and 04/02/15, 61 potential research study participants were sent letters with incorrect addresses on three different occasions. Two participants contacted the facility to say that they received letters that included their address, but another person's name instead of theirs. Because the contact database contained information from Veterans who participated in research years ago, staff assumed that this meant that the addresses in that contact database were no longer valid. However, on the morning of 04/13/15, the primary investigator (PI), regulatory coordinator, and study coordinator reviewed the problem. They cross checked the contact database with the mail out recipient list and discovered that the list had been sorted incorrectly, which resulted in up to 61 instances of Veteran A receiving Veteran B's recruitment letter. The recruitment letter(s) indicate that the study being recruited for is a "PTSD and Smoking Cessation" study.;