• by George Bilbrey , Op-Ed Contributor, April 2, 2014

If you don’t have a reengagement strategy to keep inactive subscribers from falling out of your email program, you should. But if you’re not prepared to do it right, you’ll probably do more harm than good.

Reengagement campaigns help you retain relationships with qualified subscribers: well-targeted people you’ve paid to acquire. The cost of finding them is typically many times higher than the cost of keeping them. Reengagement campaigns also help you identify deadweight in your lists -- relationships that can’t be saved -- so inactive names don’t drag down your inbox placement rates (IPR) for your active subscribers. It turns out, though, that senders who try to do the right thing by removing inactives, frequently cut the wrong people from their files, something we saw with surprising frequency in recent research.

Before I explain how this happens, I should acknowledge that not everyone agrees that mailing to inactive subscribers hurts IPR. They should. While looking at the effectiveness of reengagement campaigns, we used a sample of more than 4 million subscribers to measure correlations between non-response and deliverability. The results were clear. Analyzing 100 million messages sent from Internet Retailer 100 brands, we found at least a moderate correlation between read rate and IPR at every single mailbox provider, and especially strong correlations at Gmail, Yahoo, and Outlook. Sending campaigns with a lot of deadweight is preventing reputable mailers from reaching the inbox. It’s a fact.

There’s no shortage of deadweight, either. Roughly a quarter of all brands’ subscribers were inactive, meaning they hadn’t read a single message from that particular sender in six months or more. Brands sent roughly 20% of all mail to these subscribers, including messages designed to reengage them.

In many cases, reengagement messages worked.  People who got them read either the reengagement message or a successive message. In fact more often than not, the 33 IR-100 brands that we saw sending reengagement campaigns reactivated enough dormant subscribers to justify the effort. Not always, though.

For several of the brands sending reengagement campaigns, the tradeoff wasn’t worth it. So many of their messages failed to reach their active subscribers’ inboxes, and so few inactives started reading again, that the campaigns did more harm than good. Their reduced IPR disconnected the brand from responsive subscribers and didn’t reengage enough inactives to make up the difference.

Predictably most of the inactives who started reading again did so relatively soon after they got a reengagement message. The senders whose deliverability suffered appear to have waited too long before giving up on their inactives. We’re still analyzing the full data set to understand the optimal amount of time the combined group could expect to reengage more subscribers than they lose to weak deliverability, but on an individual basis the time span varies widely. Some senders were reengaging enough dormant subscribers weeks after sending reengagement campaigns to justify a dip in IPR; others stopped winning back significant numbers of inactives after just a few days.

It would be easy to err on the side of caution and simply cut subscribers that don’t read a message within a few days of a reengagement campaign, but for the senders that did this, it was often a mistake.Across the entire sample 4% of the subscribers who received reengagement campaigns were eventually removed from senders’ lists, but it turned out that half of them probably shouldn’t have been cut. More than 50% read at least one message -- either the reengagement message or a following message. These brands invested real marketing dollars to find people who wanted an email relationship, and then mistakenly severed that relationship and the potential revenue that came with it.

On the other hand, foregoing these campaigns and letting inactives stay on the list is a bad idea. One company we worked with ended up cutting a huge part of their inactives -- more than half. Their IPR immediately shot up  -- not just as a percentage of mail delivered -- and their raw number of messages delivered increased dramatically. In this case, deadweight was dragging down their program, and culling inactives reconnected the company with customers who wanted their mail but hadn’t been getting it.

The bottom line is that you can lose subscribers, and money, either way. Unless you know the breakeven point where giving up on dormant accounts is smarter than leaving them on the file, your email program is probably losing a revenue opportunity one way or another.