5 Lessons Learned From Testing Direct Mail Campaigns Using Mailbox – Our Virtual Testing Solution

Testing Direct Mail Campaigns

Direct mail advertising is like a snowflake. When you look at it up-close, every execution is different. But when you step back, there are consistent factors in every successful direct marketing campaign.

Over the years we have tested hundreds of pieces of consumer-facing direct mail using Mailbox, our virtual direct mail testing solution for determining which pieces will get set aside, which get opened and which have an effective call to action. We have tested everything from offers and letters to promotions, inserts, and forms.

We learned 5 things that are consistently important for direct mailers:

  1. The envelope matters, a lot
  2. Simplicity is essential, in both presentation and messaging
  3. Personalization is like walking a tightrope–you must strike the perfect balance
  4. Inserts can provide a focus and help differentiate an offer
  5. A well-targeted additional benefit can seal the deal

Let’s examine each issue and examine what’s inside.

1. The envelope matters, a lot

The envelope carries the burden of catching the eye and enticing the reader to set it aside for opening. There are four things we have noticed that make a difference.

The direct mailer envelope carries the burden of catching the eye and enticing the reader to set it aside for opening. There are four factors specific to the envelope we have noticed that make a difference.

Firstly, we have consistently seen that branded envelopes generate a higher open rate. We have proven—across mail, promotions, labels, and packaging—that the transparency of a branded envelope builds credibility. Trust is essential to beginning or sustaining any relationship.

Putting your branding on the outside signals that you are being transparent about what this communication is about.

We have also seen that putting your value proposition on the envelope can help people quickly decide if this communication is of interest to them or not. For those who are not interested in this particular promotion, being able to quickly discern this is a good thing. By not wasting their time, you enhance, rather than tarnish, your reputation. When you have a relevant communication landing at the right time, you have a better chance of making that connection.

We have found that adding an additional message to a value proposition can also make a difference in open rates. If an additional point of appeal can be made concisely, it can tip the balance in favor of setting aside the envelope and opening it.

Finally, putting personal information on the envelope, or teasing of personal information inside, will likely get it opened. But, depending on the nature of that information, it can attract or repel people. If they open the envelope just because they want to see what else you know about them, it is not setting the stage for them to be receptive to your message. In fact, it gets you off on the wrong foot.

It is critical to ensure personalization is not seen as intrusive, presumptuous or false.

One other thing we have noticed is that students and millennials are more likely to open their mail. If you are targeting that cohort, don’t be surprised if you see higher open rates, and a lower ratio of open to purchase. Whether a novel experience or mere curiosity, receiving mail can still feel special for the most digitally- minded generation.

2. Simplicity is essential, in both presentation and messaging

In an era of information overload, people don’t have the patience to spend time and energy struggling to understand what you are saying.

The most successful mailers we have tested are clean and simple, both visually and in their messaging. The right balance of text, images and—importantly—white space helps attract but not overwhelm.

Product features and benefits can be complex. Distilling them to their essence is critical, according to our research. We noticed in a test of restaurant mailers that having the price upfront and center helped readers see value immediately.

People don’t want excessive detail. They want to be informed.

There is an ever-deepening mistrust of our social institutions, including business. People are skeptical. They are highly-attuned to messages which seem too good to be true. Messages that tip toward hype often backfire.

Be concise. Be real.

3. Personalization is like walking a tightrope—you must strike the perfect balance

Direct mail personalization can create a very positive environment if the consumer takeaway is “they understand me”. But if personalization comes across more as “you presume to know me, but your message shows that you don’t,” then personalization will backfire and create a barrier. In the world of financial services, claiming to know specific behaviors or offering unsolicited preapprovals often tend to fall into this trap.

People know that the best a business can do is to help them reduce or manage a problem. Claims that offer to control or eliminate a problem create skepticism and typically don’t work, our research has revealed. Claim what is believable, and nothing more.

Personal information on the envelope, as we mentioned earlier, can get people’s haunches up before they even see the offer. That sets the offer up for failure.

Also, suggesting that an offer is a “limited time only” and that there is an “apply by” date can fall flat. After seeing a few dozen, or a few hundred of those, the apparent urgency rings hollow. After repeated exposure to this kind of message—from you and your competitors—it starts to have a reverse effect. People begin ignoring things they know are not true.

We have seen, on numerous occasions, that too much emphasis on urgency can hurt, rather than help. Being pushy doesn’t pay.

4. Inserts can provide a focus and help differentiate an offer

Mailer inserts like buck slips can immediately provide a focus and help differentiate an offer, we have observed. Because an insert is obviously different, it can be a great mechanism to quickly and efficiently describe a promotion, while leaving it to the other materials to deliver the details.


Altering the format can make people feel like they are reading something new and different. Repetition then becomes welcome and reinforcing, rather than annoying.

But too many inserts can become a distraction. And too much repetition can annoy rather than illuminate.

It’s like adding salt and pepper to a meal. Too much and it becomes an unpleasant and destructive distraction. But just the right amount is enjoyed without being noticed.

5. A well-targeted additional benefit can seal the deal

Many companies have very similar offers and benefits. Sometimes it is an ancillary benefit that pushes people over the line. If everyone offers “X,” then offering “X and Y” can make all the difference—even if “Y” is a relatively small benefit.

It is essential, our research has shown, that the additional benefit is on target. Otherwise, it suggests your offer is irrelevant.

Offering additional benefits, however, walks a fine line. Too much information and you lose people. They often become overwhelmed and don’t remember the main point.

Visual aids can be one way to reduce complexity when communicating how your offer is unique and relevant.

Infographic: 5 lessons learned from testing mailings

testing direct mail campaigns


Direct mail is challenging. But testing can help you break through the clutter and identify, improve and refine winners.

Test your direct mail campaign ideas using our Mailbox solution

Mailbox simulates real world interaction and consideration by uncovering how consumer-facing communications perform with detailed evaluation of the value proposition, messaging and communication levers.

Participants complete an online virtual exercise of sorting and stacking mail as they would at home. They can open each piece, review all pages (front/back), evaluate each piece and choose to keep or discard.

To learn more watch this short video or contact us.

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