How to 2x Your Email Results with Email A/B Testing

sendfox a/b testing

This is a guest post by copywriter Will Ward who uses SendFox for his business switchTop Keyboards and explains how to do the A/B testing in SendFox.

There’s a ton of advice out there on email marketing.

“Always use a P.S.!”

“Write in a conversational tone!”

Some of it can even get a bit weird…

“Use power words to ‘hypnotize’ your readers!”

If you’ve ever done any kind of online marketing, you know these tips can be like crack.

Personally, I know that changing just ONE word on my website has driven tens of thousands of dollars in extra sales. 💵

And the same can happen for you.

It’s important to take ACTION — and see what helps you get results for your business.

Enter the simple skill of email A/B testing…

How to Run Quick Email A/B Testing with SendFox

I first heard about A/B testing from the book In The Plex about the early days of Google.

Google execs would debate what color to make the links and thousands of other small changes that could have HUGE impacts.

To test objectively, they would test changes on a fraction of their traffic and compare it to the unchanged version.

Now you may be thinking, “sure it’s easy for Google to do tests when they have school busses full of PhDs and billions of searches per month.”

I once thought the same thing — but now I realize that that’s a dangerous limiting belief.

No matter your size, not testing can be costing your business in lost sales every time you send an email with SendFox.

And testing isn’t hard.

There are a ton of free A/B testing tools out there, and you don’t need a massive list to get valid results.

Now, SendFox doesn’t have a built-in A/B testing feature. But it’s easy to split your list and use it as your email testing platform.

Here’s how to do it:

  1. Download your list from SendFox [SendFox help article]
  2. Use Excel to randomly split it into two sub-lists [Screencast video]
  3. Upload them back into SendFox as two separate lists [SendFox help article]

Three Little Tests

Now that you can test, what should you test?

Once you get into persuasion and copywriting it’s easy to keep reading book after book.

And pretty soon you end up with a bookshelf that looks like this:

My persuasion books for email A/B testing
My persuasion books.

But one thing I’ve found is that a lot of persuasion tips are not universal.

So I went back to my stack of books and made a list of every tip I could find and started testing them, one by one.

I want to share three results I’ve gotten so far.

These were all run using my SendFox testing lists to a small ecommerce store selling parts for mechanical keyboards.

A/B split testing different email subject lines in SendFox
Split testing different subject lines.

I learned this trick from copywriter Ian Stanley. The idea is, when making your offer, it’s more persuasive to use the word “when” instead of “if”. For example:

  • Less Persuasion: “Get 15% off if you spend $50″
  • More Persuasion: “Get 15% off when you spend $50

So, using my test lists in SendFox, I ran a limited time sale offer using the two headlines above.


This one surprised me. Using “when” got twice the number of sales and pulled over twice the sales volume as the “if” email.

Ian was right — use “when” instead of “if” for better results!

Test 2. Personalized “From” Field

Here’s a peek at my Gmail “Promo” tab this morning:

My inbox this morning with all the different subject lines
My inbox this morning.

There are some brands emailing me.

There’s the finance site Seeking Alpha, and the industrial equipment site IronPlanet (where I go to live out my childhood dreams of owning a tractor).

But you’ll also see some personalized senders, with a [name] from [brand] formula. Like my buds “Ben from Flippa” and “Lizzie from Khan Academy.”

I’ve read the advice in several places that a “real name” email persona works better, but I was curious to test it myself.

I sent a standard ‘product back in stock’ email to my list. Half got the email from “switchTop Keyboards” (our brand) and the other half got the email from “Will @ switchTop.” That was the only change.


The personalized version saw a 5% lift in open rates.

If you’re regularly emailing your list, this is one of those “base hit” tweaks. It costs you nothing but lets you eke out a steady gain that will keep compounding in future emails.

There are not a lot of areas in life where you can get a “free lunch” 5 percent, but email is one of them.

Test 3. Does Free Stuff Sell?

A recent A/B testing email I sent to my audience.
A recent email that I sent customers of one of my brands.

Influence by Robert Cialdini is a classic book on persuasion.

One of his principles is the norm of reciprocity.

Simply put, the idea is that giving out free stuff can help you sell because it triggers a powerful social norm to repay an act of kindness.

Now, this sounds great in a perfect world…

But if you’ve ever given out free stuff, you know there are a TON of freebie seekers who are happy to take the sample but never buy.

So I was curious to see if a free bonus would drive more sales.

When I bought the business a few years ago, one of the most requested things was stickers.

So I had a bunch of stickers with our logo printed up and I sent a “Can I mail you a free sticker?” email to half my list.


The sticker offer email got a 56% open rate, which is way above the list average.

I then mailed the stickers, followed by one of our normal product restock alert emails.

So, did the sticker-offer-getters buy more stuff?

The short answer is no. They bought almost exactly the same amount of stuff.

Now, before I pump my fist in the air and shout “myth busted” on this test, a few notes:

  1. I got a ton of emails saying they loved the stickers.
  2. There’s probably some brand value to having a few dozen of our stickers on people’s laptops out there.
  3. Who’s to say that these customers won’t be higher value in the long-term?

Once you get beyond very black and white tests like “which subject line got opened more,” things can get murky real fast.

Testing is not a license to turn off your big picture judgement.

A Warning (and Invite)

Now I want to be really clear about something.

The goal of my testing project is not to arrive at “The 30 Persuasion Hacks that REALLY Work” or some B.S. like that.

Trying to apply a bunch of persuasion “hacks” from some book to your marketing project is a great way to sound inauthentic and scammy.

The real goal is to get better at the meta skill of testing.

Learning how to run a bunch of experiments fast and cheap so that you can find out what types of offers and appeals work for your situation.

If you’d like to read more about marketing and persuasion testing, you can join my new email list that I’m calling the “Underground Persuasion Lab.”

I run one test (sometimes on my own businesses, sometimes affiliate products, sometimes other lists) and write up the results in a weekly email.

If this sounds like your cup of tea, join me here. (And yup, this uses a SendFox form).

Once you’re on the list, I’ll send you my full list of persuasion “hacks” that I’m testing (42 so far).

And you’ll also get email updates about each new test when it runs — so you can take the same lessons into your emails on SendFox. Happy testing!

When you’re done with A/B testing, be sure to check out this great article on How to Write the Best Email Subject Lines for even more conversions.

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