The Science
This is a look at the amazing work of Feld, Frenzen, Kraft, Peters and Verhoef and their excellent study of how design characteristics affect the open (OR) and keep rates (KR) of direct mail. Completely recommend looking up the original study – it’s not light reading, but very enlightening!
The Funnel
The direct mail conversion funnel consists of three easy pieces once the item is in a prospect’s hand:
1) the percentage of people who open it (open rates);
2) the percentage of openers who don’t immediately discard it (keep rates);
3) the percentage of respondents
Often when considering a campaign, we are less likely to test the envelope and a few letterhead design cues than we are words, headline and offer. The work in this study showed just how much (like 25% much!!) a few simple variables can move the needle.
Standard Advice
There’s tons of literature quoting various untested assumptions as lore – use coloured envelopes, don’t use windows, put sales message on the envelope, long letter, short letter, enclosure, no enclosure etc etc.
Conventional advice is normally: grab attention with the envelope, get your piece opened and by association generate interest in your offer.
But, it turns out it’s not as cut and dry as that. Coloured envelopes are bad in financial services, but good in NPO mailings.
Also turns out that there’s no significant relationship between OR and KR, other than the fact that you can’t keep it unless you opened it in the first place. A good OR doesn’t translate automatically into a good KR.
In other words, it’s not enough to just get someone to open your mail.
Once the direct mail piece is opened, all the effects of the envelope are forgotten and the letter and enclosures take over.
Main Takeaways for KR & OR
The study focussed specifically on mail sent by financial service providers (FSP) and non-profit organisations (NPO).
The results for each sector were quite different. What produced positive results in financial services was sometimes damaging in the NPO. Here are some of the key findings for the financial services industry:
- Coloured envelopes reduced OR compared to plain white
- Address window had a small negative effect on OR
- Special format envelopes, teaser questions and promo designs on the back of the envelope slightly reduced OR
- The length of the headline on the letter positively affected KR.
- Including a P.S. reduced KR unless it had new information in it.
- Including the sender’s name on the front of the envelope negatively affected OR.
- A logo on the letter inside increased KR.
- Prepaid postage indicias reduced OR significantly.
- Personalisation of any included supplement marginally affected KR.
- The length of the included brochure affect KR positively, but not the letter.
- Offer details in the letter or a response option to ask for more info positively affect KR.
- Two-step campaigns positively influenced KR.
- Variance in OR is was up to 24.4% from design characteristics alone; ergo 25% of your success comes from the envelope and the design cues on the contents
The giant shoulders we stand upon:
Feld, S., Frenzen, H., Krafft, M., Peters, K., & Verhoef, P. C. (2013). The effects of mailing design characteristics on direct mail campaign performance. International Journal of Research in Marketing, 30(2), 143-159
