Increasing your non-electronic mail open rates

These direct marketing kids today, with their emails and analytics and the Facebook — they don’t know how hard it used to be.  Back in my day, we sent people letters.  You couldn’t measure open rates!  You’d just see if they sent back their check and hoped they opened it!  And the mail carrier walked uphill both ways.

The problem is that my day was yesterday.  We still can’t tell if people are opening our envelopes.  Given the amount of testing of colors and windows and teaser copy that goes into this area that can only be measured tertiarily, this is a pity.

Today’s study doesn’t entirely solve this but takes a nice step forward in understanding what gets people to open and react to envelopes.


I know I shouldn’t be talking about this right now — I should be writing about direct marketing New Year’s Resolutions, just like I should have done the year in review last week, Star Wars content the week before that, and preparing for year-end giving content in November.

And maybe I’ll do that some day, but for right now, I’m going to try to remain counterprogramming.  Think of me as the nonprofit direct marketing Puppy Bowl — if you tire of zigging, come over here and I’ll probably be zagging.


As Chekov said, if you mention the Puppy Bowl in Act 1,
you must show an image of it in Act 3.


To test envelopes, GfK has a panel of German households who give GfK the direct mail pieces they do not want at the end of each month, either opened or unopened.  The study authors (Feld et al) then looked at the impact of envelopes on the open rate and keeping rate of the mail pieces.  They looked at 68 attributes of 36 design characteristics across almost 400 nonprofit campaigns.  You can get the whole study here if you want the full list, but suffice it to say that when you are looking at what percentage of the response device in an envelope is colored and have five different segments for this, you are doing a pretty comprehensive look at the piece.

The first big result to note is that the open rate did not correlate to the keeping rate. I’ve seen this personally — when an envelope promises something the contents do not deliver, the piece is shredded with extreme prejudice.  Now on the nitty-gritty:

  • Colored envelopes decreased open rates.  I know, it’s difficult to cut through the clutter, but that apparently isn’t the way to do it.
  • Larger envelopes, questioning teasers, and a promotional design on the envelope back all increase open rates.  I would go one step further and advocate for questions that can’t be answered with a yes/no and that elicit curiosity.  While you could put “What is the capital of North Dakota?”* on your envelope, I wouldn’t recommend it.
  • Pre-stamped return envelopes increase keeping rate; postage paid on the outside envelope decreases open rates.  These may seem obvious, but you will have to assess whether the cost involved is worth the increases, as both will increase your cost per piece.
  • A testimonial from a helper increases keeping rates.  It seems like I’ve been talking about variants of these for the past couple of weeks — how social proof and authority can help your appeals, as well as how information can enhance persuasiveness among high-dollar donors.
  • Premiums can work, but expensive ones decrease keeping rates.  People like to receive things (reciprocity at work), but the idea that the nonprofit is spending more on the premium than on the mission is a significant turnoff.
  • Efforts to recruit new members decrease keeping rates. My guess here is that it’s too much too soon.  I’ve seen membership efforts do very well to existing donors (who likely want a sense of belonging), but for new supporters, it might be like proposing marriage on the first date.
  • In the letter, logos and fax numbers increase keeping rates.  Yes, fax numbers.  It also appears that having the phone number decreases keeping rates.  I have no idea why this would be.  If you do, please leave it in the comments to help illuminate us.
  • People kept letters more closer to the end of the month.  Perhaps a “more disposable income” effect at the end of the month?  I’m not sure here either.

Finally, longer letters and personalization increase keeping rates.  I’ve talked about personalization helping your efforts.  Longer, in this case, means more than one page of letter, but my guess is that there may be a sweet spot after that in the 2-4 page range.

We hear about information overload, but I would argue that there is mostly an overload of bad content generated by the same people who created Mad Libs (e.g., [number] ways to [verb] your [noun]; [number] videos that will keep you [verb]ing: number [number] will blow your mind).

A well-written letter, by contrast, can be a beautiful and effective thing.

So, the idea mail piece in this study (were cost no object) would be a larger than average white envelope.  It would not use the impersonal “postage paid” indicia, would ask an enticing question to get the potential reader interested, and the reverse would feature a strong offer.  A letter with your logo and fax number (for now, don’t question it — just go with it) that is more than one page would be on the inside, featuring a testimonial from a helper.  And your return envelope would be prestamped.

Nothing completely earth-shattering here, I would say, but these are some very solid tips for making your pieces more effective.

* It’s a trick question — both the N and the D are capitals.

Increasing your non-electronic mail open rates