I have been arguing for some time that after five years or more of email being the dominant form of direct advertising, postal mail has made a come back.

But my comments have brought the response that postal direct mail might be ok for the big corporates, but small companies simply can’t afford to advertise through the post.

I disagree – but more to the point I think that such comments reveal that we have lost track of the noble art of testing a campaign.  Let me explain why.

In days gone by, few people went dashing straight into a postal campaign, mailing out 5000 or 10,000 leaflets or brochures at a time.   Mostly they preceded the mailing with a test run.  Then if the test run worked they would move on to the full mailing, secure in the knowledge that promotion would work.

Quite how large the test mailing had to be depended on the response rate required to make a profit.   There is a formula for this but whenever I have quoted it, it has generated more confusion than illumination, so I’ll leave that until the end – and instead give a couple of examples.

Let’s imagine you want to get a 3% response rate to a postal mailing.  With this you can mail out 200 letters at random, and if you get 6 replies you know you are on course for your 3% – so you can go ahead and mail the full list.

This experiment will cost you about £100 – when you come to mail out large numbers the cost will drop as you will get postal discounts so the profit will rise.

But you should not think of this as £100 written off.  Even if you don’t get your full 3% response rate you will probably get one or two sales, which while it won’t make you a profit will reduce the cost of the experiment.

Because of this, companies that are masters of postal direct mail tend to do regular experiments with their postal mailing, often sending out several variant promotions at the same time, to find the best one.  As we have shown in the past, changing just the last two lines of a sales letter can have a major effect on the response rate.

The only problem with this approach arises if you need just a tiny response rate to make a profit.   Imagine that you make so much out of each sale that you only need a 1% response rate – then your test run should be 600.   If you make money selling to just 1 firm in 300 then you need to mail 1800 in your test run.

If you would like to talk about postal mailings, mailing lists and the ways to write the copy, please do get in touch on 01536 399 000.

Tony Attwood

PS: the formula for working out the number of items you need to send out in the trial is 6 divided by the percentage response rate required.  Six is taken as the base number, as it is just about the minimum number of replies that can be sought which will be statistically reliable for mailings of up to around 30,000.