Type of mailing and effectiveness of direct mail advertising

Abstract

Does 1st-class mail yield higher responses than 3rd-class? A professional periodical tried it out in 2 experiments one using 10,000 units with 1st- and the other 10,000 with 3rd-class mail. 1st-class mail by far was the most effective. (PsycInfo Database Record (c) 2025 APA, all rights reserved)