Most brands are judging email collection or email popup performance by the wrong metric:

Sign-up rate.

"How many emails did we collect" is the wrong KPI to optimize for.

Why? The raw number of emails collected, or even net-new email subscribers (New email subscribers - unsubscribes) only tells you a volume number, not a quality number.

You can be growing your list, and still see email revenue decline because you’re getting unqualified prospects onto your list who may never buy.

So, what do you track?

Let me show you how to tell if your pop-up form is TRULY performing…

A client of ours recently switched to a spin-to-win popup earlier this year.

Email signups climbed every month. February: 1,500 new subscribers. March: 1,900. April: pushing 2,000.

But there's a metric most brands ignore that tells you what's actually happening: Of the people who sign up, how many actually buy in that same period?

February: 10%
March: 9.8%
April: 8.2%

More signups every month, but less conversions.

Gamified popups can work, but more often than not, they attract browsers, not buyers.

The person spinning a wheel for a mystery discount isn't the same person who came to buy your product for the core desire it solves.

You're optimizing for volume, when you need intent.

You see list growth climbing and assume revenue should follow. It doesn't.

This metric tells you of the people who sign up, how many actually buy within a given time period (typically 30 days) where 80-90% of first purchases happen.

Volume feels like progress. Intent pays your bills.

Most brands won't catch this because they're not tracking this number alongside signups. They're celebrating the wrong thing.

Here's how you calculate your New Subscriber Conversion Rate (NS-CVR):

NS-CVR = (Welcome code usages / new subscribers in a period) × 100

Example:

Once you know your baseline, test it.

If you're a small team or have limited capacity, you can use orders attributed to your pop-up form in that period.

It's less accurate than true codes used at checkout that turned into a purchase in that period / new subscribers in that same period, but tracking it over months can give you a baseline.

Run your current popup against a new variant. Track both email signups AND new subscriber conversion rate. Not just volume. How many people who opted in actually bought something in the next 30 days.

If signups go up but conversion rate stays flat or drops, you're collecting the wrong people.

If signups drop slightly but conversion rate climbs, you just upgraded your list quality and your revenue will follow.

Test it. Track both numbers. Make decisions based on what drives buyers, not just subscribers.

Bigger isn’t always better. Building your email list is ABSOLUTELY an exercise in QUALITY over quantity.

Look at the total number of net-new subscribers AND the number of new subscribers who are purchasing to understand if your list growth efforts are truly working, or only LOOK like they’re working.

If you're not already familiar, Alia is a done-for-you email pop-up platform that tracks NS-CVR automatically.

No manual calculations, no spreadsheets. Just log in and see exactly which subscribers are converting and which popups are actually driving revenue.

Get a 30-day free trial for your Shopify brand:

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