The genre of sales letters: What counts as good advice?

A sales letter (or email) is designed to entice a reader to become a customer of the writer. The most common approach to training writers to create a sales letter is called AIDA, standing for

1. Attention
2. Interest
3. Desire
4. Action

It was developed by Elias St. Elmo Lewis based on his practical advertising experience in the US before the end of the 19th century. You can read more about the AIDA funnel at ProvenModels. I appreciate advice based on personal experience. I really do. Sometimes it’s all there is.

But, as a critical thinker, I value advice backed with quality data even more. I don’t mean I only trust numbers. I like the way Joseph A. Maxwell, author of Qualitative Research Design, defines “validity.”

I use validity in a fairly straightforward, commonsense way to refer to the correctness or credibility of a description, conclusion, explanation, interpretation, or other sort of account . . . the idea of objective truth isn’t essential to a theory of validity that does what most researchers want it to do, which is to give them some grounds for distinguishing accounts that are credible from those that are not. Nor are you required to attain some ultimate truth in order for your study to be useful and believable.

My quick search in research databases suggests the AIDA approach to writing sales letters is untested. That doesn’t make it a platitude. But to me it does mean a lack of validity — or credibility.

In contrast, applied linguists have identified the rhetorical moves (content + purpose) in sales letters by collecting a sample of them and then analyzing their similarites. I’ve written about a sales letter my husband and I wrote before in Pros Plan Message Content Strategically and Pros Plan Message Organization Strategically.

The table below summarizes the moves, their general purpose, and an example from our sales letter.

I teach my students several ways to maximize the credibility of their conclusions without relying on numbers. Let me share two of them with you here as they might be applied to guidance for writers of sales letters based on rhetorical moves research.

The first technique, Triangulation, requires that you present multiple and diverse types of evidence to support a single conclusion. For instance, the same rhetorical moves identified by Bhatia have been identified in studies of letters in other languages, as well as in those written in English by non-Westerners. The fact that the moves describe many diverse sales letters makes guidance based on that research credible.

The second technique, Analytic Induction, requires that you discuss any evidence you have that does not support your conclusion. For example, we didn’t follow the exact move structure from research in our letter. More specifically, we decided we could put almost all details about the offer in an enclosed brochure so move #4 (referring to enclosures) appears right after #2 (introducing the offer), which could then be very briefly covered in the letter itself.  That choice was strategic because we believed we needed to devote more of the letter’s real estate to move #3 (offering incentives), which we saw as primarily altruistic in the case of this solicitation letter. I don’t believe that would be true of sales letters, in general. So I still think rhetorical moves research is credible.

All of this explains why I rely on the rhetorical moves research rather than the AIDA model for guidance on writing a sales letter. While AIDA’s value could be tested with actual letters, rhetorical moves already have been.