Most GA4 setups go wrong for the same reason: nobody agreed what they were for. Marketing counts one thing, sales counts another, finance has a third number, and the tracking was built to whoever asked last.
A measurement plan settles that before anything is built. It isn't a technical document. It's an agreement between the teams who use the data.
What's in the template.
- Scope: the property, domains, apps, countries and environments the plan covers, and what's out of scope.
- People: every team with a stake, from paid media to finance and the DPO, with a named owner and what each signs off.
- Outcomes: primary outcomes, supporting outcomes and engagement signals, each with a plain-English definition and its system of record.
- Key events: which GA4 events count, why, whether they're used for bidding, and what is deliberately not a key event.
- Journey: the stages and drop-off points the business cares about, mapped to GA4 events.
- Rules: decisions on campaign tagging, payment providers, identity, consent, naming and who can publish tags.
- Reporting and QA: which reports are official, and how GA4 is checked against your order system and CRM.
- Change log: a version, date, owner and reason for every update.
Grey text shows worked examples for a business that takes online orders and enquiries. Yellow cells are for you to fill in.
How to fill it in.
- Agree the outcomes first. Everything else follows from what the business counts as success, and where the authoritative number lives.
- Name the owners. A team without a named person isn't involved. Delete the teams that don't apply to you.
- Be strict about key events. Purchases and genuinely qualified enquiries are outcomes. Checkout starts and call clicks are progress signals. Writing down what isn't a key event stops the list growing later.
- Settle the rules once. Campaign tagging, identity and consent decisions go on one tab, so nobody has to ask again.
- Decide how you'll check the numbers. Agree how close GA4 has to be to your order system and CRM before anyone relies on it.
- Version it. Every change gets a line in the change log, with the date it takes effect.
The article on the ideal measurement plan explains each part in more depth, including how to run the meetings.
Lead businesses: one rule matters most.
If sales decides which leads are any good, a form submission isn't success. The plan should say that "qualified lead" is a CRM outcome, and how it gets back into marketing reporting. GA4 can show the journey that led to an enquiry. It can't judge the enquiry.
What comes next.
The plan says what you need to know. The next document says exactly what the website sends: the dataLayer specification template picks up where this one stops. Before either goes to developers, the GA4 event name checker will catch names GA4 won't accept.
Download the template (Excel). It's free to use and adapt.