Email frequency: can you increase it safely?

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As the marketing world (re)discovers email, many people are asking if they can send out more email to keep sales/responses flowing through difficult times.

Experts are skeptical, citing the risks of increased spam complaints, unsubscribes and list fatigue. Short-term response boosts can come at the cost of delivery problems, damage to your brand, and long-term loss of sales/responses.

But is there a way of sending more email without incurring these problems? Is this even the right question to ask? Answers below. First, though, you need to understand three things...

1. The frequency curve

Here's a typical curve showing how profits might change as emailing frequency rises for, say, a retailer:

the email frequency curve

If you start at point A, you initially get more profits as you up frequency. At some point (B) you reach an optimal frequency level. Sending even more mail might bring additional sales, but these are outweighed by the impact of fatigue and profits fall.

Eventually, you're sending so many emails that people are hitting their "spam report" button in earnest. Suddenly (D) you're on a blacklist or three, delivery rates plummet and profits with them.

The trick to changing frequency is to test carefully, so you find the optimum frequency without slipping onto that sharp and painful profit-killing descent.

Note I say "changing" not "increasing."

It may be your current frequency is already at point C, and you might make more profits by sending less.

A recent whitepaper from Emailcenter cites the example of who tested halving their frequency to one email a week: total bookings went up.

Equally important is to note that some impacts of frequency changes take time to appear. In the example, the net benefits of less email only became apparent after three months: the results in the first week of the test gave the opposite result.

2. What do consumers tell us?

There are many studies of consumer attitudes to email that warn of the dangers of overmailing.

Here some recent stats:
  • In Merkle's "View from the inbox" report, 73% of survey respondents cited "sending too frequently" as the main reason for opting out of an email program
  • In Epsilon's "Beyond the click" email branding study, 71% of respondents said it wasn't OK for companies they know and trust to send email more frequently than they already do
  • According to a MarketingSherpa study quoted in their 2009 benchmark report, 25% of respondents who reported an email as spam gave "too much email from the sender" as a reason for doing so
Wow - increasing frequency looks a bit like a game of Russian roulette. But wait...turn those figures around:
  • 27% didn't cite "sending too frequently" as the main reason for opting out of an email program
  • 29% said it was OK for companies they know and trust to send email more frequently than they already do
  • 75% didn't report a sender as spam because they sent too much
The lesson: we're all different.

We tend to think of frequency in terms of how the whole list behaves. But the frequency/profit relationship for the list is the sum of its parts. Each address on that list has its own unique frequency/profit curve.

In other words, the optimal amount of email for one recipient isn't optimal for the next.

Equally, the optimal number of emails changes with time: I'll welcome more email promotions in the lead up to Christmas, for example.

Hang on to those thoughts.

3. Frequency is tied to value

Much of the debate about frequency ignores the fact that what you send impacts how much you can send. The problem is often not that you send too much email per se, but that you send too much of the same email. Or too much crap email.

If your emails are rubbish, then sending one email might be too much. The costs and brand damage might outweigh the paltry sales it brings in.

The more value (for the recipient) in the email, the more the frequency/profit curve shifts in your favor:

the email frequency curve

If you increase value, then...
  • you can earn more profits at the same frequency
  • recipients will respond positively to more email for longer than if you're sending rubbish
  • you can earn more profits at lower frequencies
The third point is particularly critical. We're asking, "how can we send more email?" A better question might be "How can we send less email but still raise profits?"

The answer is through value, which is why so many experts talk about relevancy, targeting, segmentation etc. All concepts designed to make your emails more valuable so you can improve results without playing Russian roulette with frequency.


Armed with these theories and insights, you can see that simply sending "more of the same" is a risky idea. You need to be more sophisticated than that.

Here some quick ideas worth testing:

Specials: the occasional one-off "high-value" email. Like a last minute offer on a for-fee webinar to your newsletter list.

Benefit emails: consider adding some emails that give, but ask for nothing in return. See the article on marketers as content publishers.

Extra messages, same email: increase message frequency, but not email frequency by piggy-backing on existing communications. For example, adding marketing messages to transactional emails or using sidebar promotions in informational newsletters.

Go with the season: if you're a ski resort, up frequency when you know people plan their winter vacation.

Let subscriber behavior and characteristics drive frequency: Loren McDonald recently wrote:

"When you send email based on your customers' actions or their place in the product or program lifecycle, your messages arrive at logical times." which I would add..."and at the 'right' frequency."

Particularly useful tactics here are trigger emails (like birthday messages or cart abandonment emails) or segmenting out your most active subscribers. If someone is clicking every time you send an email, chances are they'd welcome more.

Give people choice: let people opt-in to another email stream. Or more frequent emails (or less frequent emails). During the 2008 holiday season, for example, RadioShack invited subscribers to opt-in to a dedicated "24 days of deals" campaign. This lets recipients self-select: they tell you directly who wants more (and who doesn't).

Remember, when you start upping frequency, you begin to break expectations built over your previous mails or in sign-up forms. And you start moving along a curve which can end catastrophically.

So you need to change things with care. And you need to combine any increase in frequency with some form of real compensation for the recipient.

All the above do this by upping frequency only when it makes equal sense for the recipient. A change to adjust for different circumstances (e.g. seasonal), to offer more relevancy (e.g. trigger emails), to give more value (e.g. specials and benefit emails) or when the recipient specifically asks for more (e.g. new opt-in streams).

Any other suggestions?

More on timing and frequency | Tags: ,

Permalink | March 03, 2009 | 14 comment(s)
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Fabulous article as always - probably the best article I've ever seen on email "frequency" - as you cover so many angles...and some great quotes to boot.

I think the core issue that you addressed is the fundamental question marketers must ask themselves: How do we maximize profits and lifetime customer value? Which is very different than: How frequently can we email our subscribers/customers? If marketers would focus on this question and not "Can we send two more emails each month" - their profits and the industry's health as a whole would be much better off.

Keep up the great columns Mark!

By Anonymous Loren McDonald, on 04 March, 2009  

Thanks Loren. Agree. If you focus on the bigger issue (which I would describe as maximizing the mutual exchange of value between sender and receiver) then things like timing, frequency drop out naturally.
By Anonymous Mark Brownlow, on 04 March, 2009  

This is certainly a timely post, Mark. Lots of interest in sending more--unfortunately not enough interest in doing it intelligently. CXOs really driving increases right now.
By Blogger Chad White, on 04 March, 2009  

Great as always, Mark. Thank you!

Segmentation is the key to optimizing frequency. More email does not equal more revenue, but More Relevant Email does equal more revenue. True for email as it is with all effective direct marketing.

Thanks for taking the time to walk through WHY segmentation is so critical!

By Anonymous Stephanie Miller of Return Path, on 04 March, 2009  

Hi there - thanks for mentioning our emails.

As you say - frequency is inversely related to crapness of email relevance. A great example of this is newsletters vs triggered alerts from job or property sites. When looking for a new lair last year I actually longed to get my alerts from Rightmove giving me the instant inside track on new houses on the market. I’d be upset if I didn’t receive one for a few days! As soon as one arrived it would be opened and a quick phone conference with the lady would ensue eventually leading us buying our new home.

Once a week or so Rightmove would also send me a newsletter. Opened once - no personalisation about my house hunt, loads of stuff about buying abroad etc – whatever - delete delete delete... never opened again.

When the email is triggered by the users waiting for something to occur it is not seen as marketing but service. Another example is I discovered this story today from the Google blog email alert I have set on our brand - I always open these even with 100+ other emails left sadly unread today...

At toptable we're attempting to achieve the personalisation of a trigger alert with the traditional long form newletter but have a way to go yet to fully crack it. We’re also introducing our own trigger emails based on restaurants starting new offers – we’ll let you know how these programs go in a future case study…
By Anonymous Mat Braddy, on 04 March, 2009  

Thanks Chad, Stephanie.

Mat - thanks for sharing those insights. Love the quote "When the email is triggered by the users waiting for something to occur it is not seen as marketing but service."

Looking forward to more case studies.
By Anonymous Mark Brownlow, on 04 March, 2009  

As a follow-up, Stephanie posted some great ideas for "additional" emails here.
By Anonymous Mark Brownlow, on 04 March, 2009  


Really enjoyed this one. You nailed many of the points.

For me it's always been about knowing your viewers(customers) threshold.

Companies need to determine how their brands email frequency will effect their viewers needs.

Dave Dabbah
By Anonymous Dave Dabbah, on 05 March, 2009  

Being the author of the whitepaper featuring the toptable case study I thought it would be worth putting my opinions down.

1. Optimum frequency is different for everyone. Mark is right if you have rubbish or irrelevant email something like one email a week will be too much. But then again if I receive rubbish email after about the 3rd time I don't open again, even if frequency is low.

If toptable had not combined the shift in frequency with content being tailored around location I bet we would not see the same positive results (and now I get people come up to me and say how much they love the toptable emails nowadays and cannot wait to receive them!).

2. The main problem with frequency is not you and I. Marketers know the score in that sending too often damages the list.

Unfortunately senior management see email as a tactical tool. Hands up who has a CEO who has said something like:

"Sales are low this week - lets send an email!"

Yet they don't see (or have to deal with) long term list fatigue issues.

3. People don't just unsubscribe or report as spam. They just ignore or delete your emails.

There is no direct metric for ignored or deleted so a lot of marketers don't realise they have a problem.

Sean Duffy, Emailcenter
By Anonymous Sean Duffy, Emailcenter, on 05 March, 2009  

Thanks Dave.

Sean - thanks for sharing those super extra insights. Point 3 especially.
By Anonymous Mark Brownlow, on 05 March, 2009  

I wouldn't put much weight in surveys about how often people want to receive mail.

What people say is often different from what they do.

You need to test for your own list to determine what is the best frequency.

The people complaining in surveys about too much mail may never buy anything anyway, so who cares what they say? Especially if they are making false spam complaints- they have no credibility.

I know people who mail daily and make a fortune.
By Anonymous Chris, on 06 March, 2009  

Hi Mark,

Great post - another good one on frequency is Dela Quist's Maximising ROI without overmailing - how to determine the right send frequency for your email campaigns

By Anonymous Kath Pay, on 06 March, 2009  

Chris, agree with your point that it's about finding the right frequency for your actual list.

But disagree that we can ignore the moaners. While the spam complaint may have no credibility with you, it does with the ISPs.

Kath - thanks for the link!
By Anonymous Mark Brownlow, on 06 March, 2009  

Nice Post...
By Anonymous Chefpiper, on 19 November, 2009  

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