It isn’t very often that you see a case study revealing side-by-side testing results on print vs. email, so when I ran across this one from Data Services Inc., it caught my eye. The case study is older (posted on DSI’s blog in 2013), but it’s conclusions are still valid. It involves a nonprofit that decided to test the effectiveness of CTAs in both direct mail and email.

The testing was done by The Danish Cancer Campaign, and the test not only measured the effectiveness of CTAs in each channel, but also each channel’s impact on recall and decision to respond.

The campaign was designed to boost participation in The Danish Cancer Campaign’s charity lottery. The nonprofit selected three groups of 2,000 from its database of registrants to its previous lottery.

First, each past participant was sent a written invitation to participate in the annual fundraiser. Two weeks later, it sent one of three reminder messages to the test groups via email or postal mail.

• Group 1 had opted in to receive emails and received an email reminder.
• Group 2 had opted in to receive emails but received the reminder by postal mail.
• Group 3 had not opted in to receive emails and received a reminder letter by postal mail.

To encourage participation, recipients of each communication, regardless of channel, were given additional lottery numbers.  This is how the nonprofit tested recall. The results were determined by follow-up phone calls.

What were those results? The letter showed “overwhelming power,” according to the case study. “Only 25% of Group 1, who received the email reminder, recalled receiving the reminder email,” notes DSI in the write-up. “However, 58% of Group 2 and 55% of Group 3 spontaneously recalled the reminder direct mail letter.  Even after prompting, groups two and three had better recall of the reminder letter than the email community, recalling at 85% and 80%, respectively, against 63% for the email recipients.”

In addition, DSI reports that 12% (Group 1), 24% (Group 2) and 29% (Group 3), respectively, had reached their decision to play in the charity lottery only after receiving the reminder letter. “In short, the direct mail letter produced twice the response of the email reminder,” DSI writes.

In today’s world of high pressure to go with digital marketing, it’s great to be reminded that direct mail still packs a punch, and this case study makes that point in spades.  This doesn’t mean that direct mail is always going to win the ROI battle over email, but very often, it does. That’s why it’s important to encourage clients to test.  They might not believe it until they see the numbers.