Do offline and online go hand in hand? Cross-channel and synergy effects of direct mailing and display advertising

Despite the rise of digital, direct mailing as a marketing communication tool remains relevant and widely applied in practice. Nevertheless, research into the effectiveness of direct mailing in the online environment is scant. Key questions that remain entail how direct mails affect different online and offline consumer activity metrics throughout the purchase funnel and how they interact with digital marketing communication tools. The current paper, therefore, investigates these two questions by conducting two studies. First, we focus on the effect of direct mailing on zip-code level upper, middle, and lower funnel performance metrics over time by analyzing quasi-experimental data from a large European insurance firm. The results reveal that direct mailing significantly influences consumer activity metrics in the online channel (i.e., online search and clicking behavior), in support of cross-channel effects of direct mailing. Moreover, direct mailing is shown to be effective throughout the purchase funnel, both directly and indirectly, with a positive net sales effect. Second, we study the joint effect of direct mailing and display advertising by analyzing field experiment data from the same insurance firm. The results show positive synergy between direct mailing and display advertising. Therefore, despite the rise of digital, direct mailing still serves as an effective marketing tool, both by itself and in combination with digital marketing.