How many of this summer's customers already came last summer?

There is one figure that decides whether your business is growing or replacing, and almost no venue has it: what percentage of this season’s customers were already there last season.

Without it, two businesses turning over the same amount look alike. With it, one is building a base and the other is buying new customers every year at market price, for ever.

Why almost nobody has it

Because working it out means recognising the same person across two purchases a year apart, and that demands something this sector handles badly: a customer identity that survives changes of email, purchases made by a friend, and the fact that half the tickets get bought in the name of whoever pays rather than whoever walks in.

The easy way out is to require registration. And it is a trap: you end up measuring only the people who agree to be measured, which is one specific profile and not your business. A club basing its repeat rate on its membership base is measuring its membership base, not its repeat rate.

How to work it out with what you already have

1. Export this season’s purchases and last season’s.
2. Normalise the email — lower case, no spaces, Gmail dots collapsed — and the phone number to international format. That alone clears most of the duplicates.
3. Match the two sets. The overlap percentage is your floor for repeat rate: the real one is higher, because some people came back on a different email.

It is a floor and not an exact figure, and that is precisely why it is useful: a floor that rises season after season is the cleanest signal there is that the business is building something.

The three numbers that go together

Repeat rate on its own only gets you halfway. It comes with two more, and all three are worked out from the same purchase data without asking anyone for anything:

• Recency — how long since they last came. It is the only one of the three that moves on its own: it climbs every day that person does not show up, so it works as an alarm without anyone programming one.
• Frequency — how many times a year. This is where the lever is: someone who comes twice and could come three times is an actionable segment; someone who comes once and is not coming back is not.
• Value — how much they leave. Without this one, the other two reward the person who comes constantly and spends nothing.

And the trap in visitor-heavy markets

If a large share of your crowd is visitors, your repeat rate is going to look bad and it is not: a visitor is not coming back next month. The figure has to be read separating local from visitor, or you are measuring two different businesses with the same yardstick and penalising the one that works.