In chemistry there’s a concept called a “half-life.”
From what I understand, the half-life is the amount of time that it takes for radioactive material to decay to the point where it’s giving off half as much radiation as it did on day 1.
This happens at a very steady, predictable rate.
Well, emails have a “half-life” too.
And it’s useful to keep this in mind when you’re planning out an email course or series.
This is relevant to a question I got from subscriber Sarah :
I have a free email course I’m getting ready to launch. It’s 6 days of learning, not including the sales emails that will go out afterward. Do you recommend sending an email every day and doing the whole thing in six days? or every other day (12 days)? They’re not the world’s shortest emails.
This is an easy one:
Send the emails back to back to back.
There’s not much to gain from waiting an extra day between messages.
Individual emails have a “decay rate” in terms of open and clicks.
My experience is that you get most of the response within the first 24 hours.
Sarah’s question made me curious, though, so I took a peek at several of my recent broadcast emails to get more specifics.
Here’s what I found:
74% of opens and clicks occurred in the first 24 hours.
And another 15% came in the second 24 hours.
Only 11% came after the first 48 hours.
This pattern is consistent across multiple broadcasts.
I don’t have access to hour-by-hour data, but based on the above I’d put the “half-life” of an email around 8-12 hours.
To Sarah’s question, the length of the email isn’t really a factor.
It’s more a question of pure marketing “chemistry.”
If they haven’t read your email within 24 hours, they’re unlikely to see it.
And it’s better to keep the email train movin’ rather than wait for the stragglers to catch up.