For the best part of a decade, marketers justified their email budgets with a single number. Email, they said, returns $42 for every $1 you spend. It appeared in pitch decks, board reports and conference keynotes. When independent researchers finally ran proper holdout tests, the real figure came out closer to $12.
The correction comes from Ivana Taylor, who traced the famous $42 statistic back to its origins in a widely shared analysis published on June 24. The number, she points out, came from surveys run by Litmus, Constant Contact and the DMA — all companies that sell email marketing products. When researchers with no stake in the answer measured email's contribution using controlled holdout groups, the return landed nearer 12 to 1. Still the best-performing channel most businesses own. Just not the figure everyone had been quoting.
The gap matters more than it first appears. A small business owner who measures real results against a benchmark that was never accurate ends up drawing the wrong conclusions — feeling like a failure for hitting a number that was inflated at the source. The headline stat was built by the people with the most to gain from a big headline stat.
The same week, Litmus published a companion piece, "Why They're Just Not That Into Your Emails," that quietly undermined a second sacred metric. Delivery, the figure your email platform reports, simply means a receiving server accepted your message. Deliverability is whether it actually reached the inbox. Mailbox providers like Gmail and Outlook constantly weigh sender behaviour, and the single biggest improvement most senders can make is to send to fewer, more engaged people. A smaller, active list reliably outperforms a large, dormant one.
Then there is the open rate, which has been broken for years. Apple's Mail Privacy Protection pre-loads images on behalf of users, generating an "open" whether or not a human ever looked. Litmus data puts Apple Mail at roughly 58% of all opens, with more than half of total opens now sitting behind that privacy filter. A dashboard showing a 45% open rate is, in large part, counting Apple's servers rather than your readers. The figure that once told you whether a campaign worked now tells you very little at all.
What this reveals is straightforward enough. The numbers that the email industry has trained owners to chase — the $42 return, the open rate, the delivery percentage — were either supplied by vendors with an interest in optimism or quietly hollowed out by privacy technology. The quieter, independently measured story is less flattering and far more useful.
For anyone running a list, three practical conclusions follow.
Stop treating the open rate as a success metric. It is now closer to noise than signal. Measure clicks, replies, unsubscribes and, where you can, actual revenue per send.
Prune before you grow. Cutting inactive subscribers improves both your deliverability and your real returns. A list of 2,000 people who want to hear from you beats 10,000 who have forgotten they signed up.
Recalibrate the benchmark. Plan around something like 12 to 1, not 42 to 1. That is still a return most marketing channels cannot touch — it simply needs to be true.
The number was inflated. The channel was not. Email remains the most dependable owned asset a small business has, which is precisely why it deserves honest measurement rather than borrowed marketing.