GA4 Setup: Get Your Tracking Right Before You Spend on Ads

Team reviewing GA4 conversion tracking and Google Ads performance data on laptop

If your tracking is wrong, your decisions are wrong. It’s that simple. 

Most businesses install GA4, see traffic numbers, and assume everything is working. But when you look closely:

  • Conversions aren’t firing properly

  • Forms aren’t tracked at all

  • Events are duplicated and results are inflated

  • Google Ads is optimising against the wrong signal

  • Revenue isn’t connected to campaigns

And then people say, “Google Ads doesn’t work.”

It’s not Google. It’s the data. So, before you increase your spend, make sure your tracking correct.

What Is a Proper GA4 Setup?

A proper Google Analytics 4 setup connects website activity to real business outcomes. It is not just installing a tracking code.

A correct GA4 setup in the UK typically includes:

  • Defined conversion events for real leads and sales

  • Accurate event parameters

  • Clean GA4 property configuration

  • Proper Google Ads integration

  • Sensible attribution settings

  • Tested and verified tracking

You should be able to answer clearly:

  • Which campaign generated this enquiry?

  • Which keyword drove this sale?

  • What is my real cost per lead?

  • What is my actual return on ad spend?

If you can’t answer those confidently, your tracking data cannot be trusted.

How Do You Know If Your GA4 Tracking Is Wrong?

Here are common warning signs:

  • Your lead numbers differ between GA4 and Google Ads

  • Conversions suddenly drop after a website update

  • Every page view is counted as a conversion

  • Cost per lead fluctuates wildly without explanation

  • You recently changed website platform or forms

If any of that sounds familiar, a GA4 audit is usually the first step.

What Does a GA4 Setup or Audit Actually Involve?

It’s not a quick settings tweak. A proper Google Analytics 4 setup means checking the full chain, from ad click to recorded conversion, and making sure nothing breaks along the way.

1. Audit the Current GA4 Installation

Start with what’s already installed.

Check:

  • Is GA4 installed correctly?

  • Is it duplicated?

  • Are events firing as intended?

  • Are conversions aligned with real business goals?

  • Is Google Ads importing the correct actions?

Forms and checkouts should be tested manually. DebugView can help confirm events in real time, but it doesn’t always capture everything. Always cross-check events in GA4 reports and Google Ads to confirm data is being recorded properly.

2. Google Tag Manager Setup (If Used)

Many tracking problems sit inside Google Tag Manager. So, ensure that your GTM is properly configured, which includes:

  • Accurate triggers

  • Correct tag firing

  • No duplicate events

  • Proper consent mode behaviour

  • A structured DataLayer

One incorrect trigger can distort months of reporting. If GTM is part of your setup, review it alongside your GA4.

3. GA4 Conversion Tracking and Mapping

Not every interaction should influence bidding. 

Conversion mapping should clearly separate:

  • Primary conversions that drive automated bidding

  • Secondary events for insight only

  • Micro conversions that should not affect optimisation

If Google Ads is set to optimise for page views, button clicks, or other low-value actions, it will happily deliver more of those. It will unlikely deliver customers you want.

4. GA4 and Google Ads Integration

Only once GA4 is clean, shoul you integarate it with Google Ads. Integration includes:

  • Importing the correct conversions into Google Ads

  • Removing redundant or broken actions

  • Aligning bidding strategies with genuine outcomes

  • Checking attribution windows match the sales cycle

Poor integration between GA4 and Google Ads is one of the most common causes of wasted ad spend.

Why GA4 Setup Matters Before Scaling Ads

Budgets and bidding strategies usually get most of the attention. Tracking doesn’t. But if your Google Analytics 4 setup isn’t accurate, increasing spend can amplify existing issues rather than improve results.

Clicks are easy to count.
Revenue takes a bit more care to measure properly.

If you want your ads connected to real business outcomes, your GA4 setup needs to be reliable first. If you’re unsure whether your data reflects what’s actually happening in the business, it’s worth reviewing your tracking before increasing spend.

FAQ: GA4 Setup UK

How long does a GA4 setup take?

A basic setup can take a few hours.
A full audit and conversion mapping process usually takes longer, especially if Google Tag Manager is involved.

Do I need Google Tag Manager for GA4?

Not always, but for more advanced tracking and cleaner event management, GTM is usually recommended.

Can I rely on GA4 without testing it?

No. Events and conversions should always be manually tested before being trusted for optimisation decisions.

Should GA4 and Google Ads use the same conversions?

They should be aligned, but not necessarily identical. Primary bidding conversions should reflect real business outcomes, not engagement metrics.

Author

Hope Varnes is a Chartered Marketer with over 15 years experience in digital marketing. She specialises in Google Ads, PPC, conversion tracking, data analytics, and marketing strategy. She has a Master’s in Digital Marketing and eCommerce and is Google Certified. She is an expert in leveraging digital platforms to drive brand awareness, lead generation, and revenue growth.