The U.S. Postal Service is asking catalog mailers not to forsake paper mailings – and providing survey evidence to back up its request.

Mailed catalogs reinforce online marketing efforts, to a point where recipients are nearly twice as likely make a purchase at a Web site than non-recipients. Furthermore, catalog recipients spend 16% more, and were 15% more likely to make additional online transactions.

The study might be perceived as a move by the USPS to protect its market share. The executive summary begins “Now that we’re firmly plugged into the Internet age, some are tempted to question the relevance of direct mail – specifically, catalogs – in today’s online shopping world,” begins the USPS’s study.

While the study focused primarily on catalogs, it did point out that even flyer mailings generated additional sales. While 15% of targets receiving catalogs went onto Web sites to make a purchase, 13% of those sent a flyer made an online purchase, too. Only 8% of a control group of targets made a purchase without being spurred by a mailing piece.