Direct Mail

A few weeks ago, I asked our community about their most pressing print marketing challenges. The top concern? "How to find the right segment" followed closely by "What drives conversions?"

This post answers both questions definitively. If you've been dismissing direct mail as outdated or ineffective, prepare to be surprised. You'll discover why nearly half of conversions happen 5+ weeks after delivery, how one simple scoring method can predict conversion rates with stunning accuracy, and why the best campaigns are generating over 1000% ROAS.

You'll get actionable insights from analyzing over 1.1 million direct mail pieces, including which customer segments convert at 15.64% (versus just 1.39% for others), why timing your measurement window wrong kills campaign ROI, and how to use the RFM product score to transform your targeting strategy.

Imagine turning every euro of direct mail spend into €10+ of revenue, or knowing exactly which customers are 8x more likely to convert before you even print the first piece. This research from 43 online retailers shows exactly how.

A huge thank you to CMC for conducting this comprehensive study and sharing these insights with our community. The RFM segmentation findings alone will solve your biggest targeting challenges from day one.

What Really Drives Conversion in Direct Mail?

Do you have a discount voucher lying around, waiting for the right moment to be used? If so, you are not alone. Receiving a letter with a printed offer still stands out of the noise of digital marketing. Direct mail continues to be one of the most underestimated channels—precisely because it works.

But what makes it work? Which customer segments actually convert? What kind of return can marketers expect—and when?

The CMC Print-Mailing-Studie 2025 addresses these questions using data from more than 1.1 million letters sent by 43 online retailers. The study examines segment performance, response timelines, and profitability, providing a detailed picture of what drives success in direct mail campaigns.

Timing is Critical: Understanding the Conversion Window

One of the key insights from the study is the delayed response curve of print mailings. Only 37 percent of conversions occurred within the first two weeks after delivery. By contrast, 47 percent took place five weeks or later.

This highlights one of the unique strengths of the channel: longevity. Unlike digital messages, print mailings often remain visible for weeks—pinned to a board, placed on a desk, or tucked into a kitchen drawer. This physical presence extends the opportunity for conversion far beyond the moment of delivery.

Campaigns that fail to account for this long response window risk underestimating the true impact of direct mail.

Segmenting for Success: Insights from RFM Analysis

Most readers will be familiar with the RFM model — if not, it is worth revisiting, as its influence on print campaign performance is both substantial and consistently measurable.

Customers who had recently made a purchase were significantly more likely to respond. Those in the most recent segment achieved a conversion rate of 5.8 percent — almost twice as high as those whose last purchase was further in the past.

Purchase frequency also played a key role. Customers with five or more previous transactions reached conversion rates as high as 8.4 percent, compared to only 2.5 percent among one-time buyers.

Finally, monetary value proved to be a reliable predictor of responsiveness. Customers with high average order values converted at a rate 55 percent higher than those in the lowest spending group.

These findings confirm that segmentation based on customer behavior is not merely theoretical but a practical and measurable lever for improving performance.

A Remarkably Strong Indicator: The RFM Product Score

In addition to analyzing Recency, Frequency, and Monetary Value independently, the study also examined the RFM product score — a composite metric calculated as R × F × M — and found an even stronger correlation with conversion behavior.

When customer segments were sorted by their RFM product score, conversion rates followed an almost perfectly descending curve. Customers with the highest score (125) converted at 15.64 percent, while those with a score of 1 converted at just 1.39 percent.

This analysis highlights that the RFM product score is a highly predictive and efficient metric. It captures not just one behavioral dimension, but the overall quality and value of a customer relationship, making it an exceptionally powerful tool for prioritizing target groups.

Measuring Financial Impact: ROAS and Cart Value

The financial return of direct mail was also compelling. On average, campaigns delivered a Return on Advertising Spend (ROAS) of 1011 percent — meaning that every euro invested generated €10.11 in revenue.

This result was further supported by a 13 percent increase in average cart value compared to previous purchases, confirming that direct mail not only drives conversion but also increases order size.

Notably, the highest ROAS was achieved in segments with the largest average order values. While conversion rates were somewhat lower in these groups, the value of each transaction more than made up for it. For example, customers with shopping carts above €150 generated a ROAS of over 2100 percent, compared to 491 percent in the lowest bracket.

These figures underscore the importance of aligning direct mail targeting with customer value, not just likelihood to respond.

Conclusion

Three key conclusions can be drawn from the CMC Print-Mailing Study 2025.

First, timing is essential. Nearly half of all conversions occur five weeks or more after delivery, emphasizing the lasting presence and impact of printed mail.

Second, behavior-based segmentation consistently delivers results. Customers with higher recency, frequency, and monetary scores convert at significantly higher rates, confirming the value of data-driven audience selection.

Third, profitability scales with customer value. High-spending segments not only generate more revenue per transaction but also yield significantly higher ROAS.

In addition, the study shows that the RFM product score (R × F × M) is one of the strongest available predictors of conversion. As the composite score declines, conversion rates fall in near-linear fashion — offering marketers a simple but powerful way to rank and prioritize their audiences.

Taken together, these insights provide a robust foundation for using direct mail not only as a branding channel, but as a high-performing, data-driven instrument for measurable growth.

About the Guest Author

The Collaborative Marketing Club (CMC) is a German dialog marketing agency specializing in conversion rate optimization and ROAS improvement for print marketing campaigns. Since 2015, CMC has managed campaigns for over 350 companies and handled 15 million print mailings in 2023 alone.

Each year, CMC partners with Deutsche Post to publish the CMC Print-Mailing Study, which analyzes the performance of print mailings to existing customers of online retailers. The study provides benchmark metrics including conversion rates, order timelines, cart values, and ROAS, with detailed RFM analysis showing how customer segmentation impacts campaign performance.