TL;DR: Before you scale Google Ads spend, check your GA4 setup and your conversion tracking. Google’s automated bidding optimises towards the conversion actions you set as primary, so inaccurate or duplicated conversions push spend in the wrong direction. GA4 adds the wider view of what people do on your site. Confirm which actions drive bidding and test them end to end, then increase budgets.
Your campaigns are working, so the next step feels obvious: increase the budget. Before you do, check your GA4 setup and the conversion tracking behind your Google Ads account. Google’s automated bidding learns from the conversions you tell it to optimise for. If those conversions are wrong, a bigger budget buys more of the wrong result.
This guide explains how GA4 and Google Ads conversion tracking fit together, then gives you a checklist to run before you scale. For the wider picture on reporting, read our guide on how to measure campaign success.
What does a proper GA4 setup include?
A proper GA4 setup includes a correctly configured property, the Google tag on every page, enhanced measurement that you’ve checked against your site, key events that reflect real business outcomes and a link to your Google Ads account. GA4 then gives you a detailed view of how people use your site after they arrive.
Google’s GA4 setup guide sets out the basics:
- Create an account and a GA4 property. You set the reporting time zone and currency at this stage. For a South African business, choose South Africa time and the rand (ZAR).
- Add a web data stream. This connects your website to the property.
- Install the Google tag. You can use your website platform’s built-in integration, paste the gtag.js snippet into the head of every page, or add it through Google Tag Manager.
- Configure enhanced measurement. This GA4 feature collects common interactions automatically, such as scrolls, outbound clicks, file downloads and form interactions. It still needs checking. Google’s enhanced measurement guide notes that you must make sure no personally identifiable information is collected, and form tracking should be tested on your own forms.
- Verify the data. Use DebugView to confirm events and parameters are arriving correctly. Data shows in the Realtime report within minutes, but most data in standard reports takes 24 to 48 hours to process fully, according to Google’s troubleshooting guide.
GA4 also tracks organic visitors, which helps you assess your SEO performance. Measuring return on investment also needs cost data and real outcomes such as sales.
Why do GA4 setup and conversion tracking matter before you scale?
Accurate conversion tracking matters before campaigns scale because Smart Bidding, Google’s automated bidding, adjusts bids towards the conversions or conversion value you set as goals. Those conversions can come from the Google Ads tag or from GA4 key events you import, and many accounts use both. If they’re inaccurate, a larger budget amplifies the error.
GA4 is helpful for this, but it isn’t the only route. Google’s conversion tracking guide explains that you can track conversions with the Google tag directly in Google Ads or import key events from GA4, and that some accounts combine the two depending on what each conversion action needs. What matters for bidding is that the actions used as goals are accurate.
The same applies to Performance Max, Google’s automated campaign type that serves ads across its channels from one campaign. Google’s Performance Max guide says it needs conversion goals to run.
Here’s how a small error grows. Say your account counts visits to your contact page as a primary conversion. Smart Bidding then bids for more people who land on that page, including those who never submit the form, and your real enquiries look expensive by comparison. This only happens when that page view is part of the goals used for bidding, which is why the next section matters.
Fixing tracking after you scale also takes time. Google suggests judging Smart Bidding over periods with at least 30 conversions, or 50 for target ROAS, according to Google’s Smart Bidding guide. That’s guidance on evaluation rather than a launch requirement, and lower-volume accounts need longer windows. Significant changes, such as a change to your conversion goals, can also send a campaign into a learning period, according to Google’s guide to learning periods. How much a campaign is affected depends on the campaign and the size of the change.
How key events differ from bidding conversions
These terms are easy to confuse.
- Key events (GA4): a key event is an event you mark as especially important to your business in GA4, such as a purchase or a completed enquiry form. As Google’s guide to events and key events explains, a key event on its own is an analytics label. It doesn’t automatically become a Google Ads bidding goal.
- Conversion actions (Google Ads): a conversion action is what Google Ads counts as a conversion. It can come from the Google tag, an imported GA4 key event, an offline import from your CRM or a phone call.
- Primary and secondary actions: Google’s guide to primary and secondary conversion actions explains that primary actions are used for bidding and appear in the Conversions column. Secondary actions are used for reporting and appear in the All conversions column. Tracking an action doesn’t mean you have to bid on it.
According to Google’s guide to GA4 conversions in Google Ads, conversions created in Google Analytics are set as secondary by default. You change them to primary in Google Ads if you want them to drive bidding.
Watch for two kinds of duplication. The first is an event that fires twice for one action, such as a thank-you page that counts again every time someone reloads it. The second is the same outcome counted by two primary conversion actions, such as a Google Ads tag and an imported GA4 key event that both record the same form submission. Either one inflates your results and misleads bidding.
If your content drives enquiries, track engagement on those pages as secondary actions or in GA4. You’ll see which content marketing pieces lead people towards a conversion without asking Google to bid on them. Reliable key events also give you a yardstick for conversion rate optimisation, which means improving the share of visitors who complete valuable actions.
How do you connect GA4 to Google Ads?
You connect GA4 to Google Ads in GA4’s Admin area, under Product links, by choosing Google Ads links. You need Editor access or above in GA4 and administrative access in Google Ads. Linking lets the two platforms share data, including key events you can import as conversions and audiences you can use for remarketing.
According to Google’s guide to connecting Google Ads and Analytics, the link gives you four main benefits:
- Conversion import: you can create Google Ads conversions from your GA4 key events.
- Audiences for remarketing: you can reach people again based on what they did on your site. Eligibility depends on Google signals or user-provided data collection being switched on, and on the consent your visitors give.
- Ad data in GA4: Google Ads clicks and cost appear in your GA4 reports within 48 hours.
- Conversion reporting: you can view the performance of your Google Ads conversions inside GA4.
Linking doesn’t make the numbers identical. Google lists several reasons the two platforms report different conversion totals. Google Ads records a conversion against the date of the ad click, while GA4 uses the date the conversion happened. Counting settings, conversion windows, invalid click filtering and import delays of up to 24 hours also play a part. Expect some difference, and investigate large or sudden gaps.
A linked setup also shows your Google Ads management team what happens after the click.
Lead quality and offline conversions
For many South African service businesses, the useful question is which leads turn into revenue. Conversion values let you tell Google that some actions are worth more than others. A quote request for a large project can carry a higher value than a newsletter sign-up. Value-based bidding strategies, such as Maximise conversion value or target ROAS, then optimise towards that value instead of raw volume.
If your sales happen after the first enquiry, by phone or in a meeting, offline conversion tracking closes the gap. Google’s guide to offline conversion imports explains how you can measure sales or qualified leads that happen after an ad click. Google now recommends enhanced conversions for leads, an upgraded version that uses hashed first-party data. First-party data is information your business collects directly from its customers.
Don’t confuse two similar names. Enhanced measurement is the GA4 feature that collects site interactions automatically. Enhanced conversions is a Google Ads feature that sends consented, hashed first-party data, such as email addresses, to improve conversion matching. In a case study on Google’s enhanced conversions page, UK retailer MandM Direct reported 3% more conversions on Search and 20% more on YouTube. Google notes that results vary by advertiser. It’s another reason to look after your first-party data.
In South Africa, the Information Regulator monitors and enforces compliance with the Protection of Personal Information Act (POPIA). Google’s your first-party data lets your tags respect each visitor’s consent choices. Ask your legal or compliance adviser what your business needs.
The settings that shape your GA4 analysis
Two GA4 settings affect what you can analyse later. Neither one affects Smart Bidding, though both matter when you review performance.
Data retention
Standard GA4 properties let you keep event-level data for two months or 14 months, according to Google’s data retention guide. The setting doesn’t affect standard aggregated reports. It does affect explorations and funnel reports, where a date range older than your retention period shows no data. Demographic and interest data is always kept for two months.
Setting retention to 14 months lets you compare this season with last year’s in explorations. Change it early, because a longer setting can’t bring back detail that has already expired.
Data thresholds
GA4 sometimes withholds rows of data to stop anyone working out the identity of individual users. Google’s guide to data thresholds says this is most likely with demographic data, or with search query data when user numbers are low. Thresholds are set by the system and you can’t adjust them directly.
Your report configuration still makes a difference. Google’s reporting identity guide notes that the Blended and Observed identity options are subject to data thresholds. Narrow date ranges with low user counts are also more likely to be affected, so widen the date range when a report looks incomplete.
What should you check before increasing ad spend?
Before increasing ad spend, check that the conversion actions used for bidding are accurate and counted only once. Then test a real conversion and allow for processing delays before you judge the results.
- Bidding conversions: list every primary conversion action and confirm each one reflects a real business outcome.
- Duplicates: check that no event fires twice for one action, and that no outcome is counted by two primary conversion actions.
- Values and lead quality: assign conversion values where actions differ in worth, and consider offline imports if sales close later.
- Consent: confirm your consent banner and consent mode settings work as intended.
- GA4 link: if you import GA4 key events, confirm the link is active and each imported conversion is set to the role you intend.
- Data retention: set event data retention to 14 months for analysis.
- End-to-end test: complete a real conversion on your site. Check it in DebugView or the Realtime report, then allow up to 48 hours for standard GA4 reports and up to 24 hours for GA4 imports to show in Google Ads.
Fix the foundations, then scale
Results at a higher budget still depend on demand and competition, and returns can taper as spend grows. Accurate conversion tracking makes sure Google’s bidding works towards the outcomes that matter to your business.
Start with clean primary conversion actions and a working Google Ads link. Then use GA4 to understand what happens on your site, and run a test conversion before you raise spend.
Not sure where your setup stands? A digital audit from our team will show you what’s tracking correctly and what to fix first. As a Google Premier Partner, we’ll help you scale on data you can trust.
Book a digital audit with our team
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Frequently asked questions about GA4 setup
Do I need GA4 to use Smart Bidding in Google Ads?
No. Smart Bidding needs accurate conversion tracking, which you can set up with the Google tag directly in Google Ads or by importing GA4 key events. GA4 adds a wider view of how people use your site, which helps you judge performance beyond the conversion count.
How long does GA4 take to show data?
Data from a correctly installed Google tag appears in the GA4 Realtime report within minutes. Most data in standard reports takes 24 to 48 hours to process fully. Once you link Google Ads, its click and cost data appears in GA4 within 48 hours.
What’s the difference between a GA4 key event and a Google Ads conversion?
A key event is an event you mark as important in GA4, such as a purchase or a completed lead form. A Google Ads conversion action is what Google Ads counts and can bid on. You can create a Google Ads conversion from a GA4 key event, but conversions created in Google Analytics are set as secondary by default, so they don’t drive bidding until you make them primary.
How long does GA4 keep my data?
Standard GA4 properties let you set event data retention to two months or 14 months. The setting affects explorations and funnel reports, and standard aggregated reports are unaffected. Increasing retention doesn’t restore detail that has already expired.
Why don’t my GA4 and Google Ads conversion numbers match?
GA4 and Google Ads often report different conversion totals. Google Ads records conversions against the date of the ad click, while GA4 uses the date of the conversion. Counting settings, conversion windows, invalid click filtering and import delays of up to 24 hours also cause differences.