GA4 (Google Analytics 4) is Google's analytics tool that measures website and mobile app traffic in a single property. What sets it apart from the old Universal Analytics is the data model: instead of sessions and pageviews, GA4 records every interaction as an event. Standard Universal Analytics properties stopped processing data on July 1, 2023; today, "Google Analytics" means GA4.
How does GA4 work?
In GA4 the unit of measurement is the event. Viewing a page is page_view, downloading a file is file_download, and submitting a form is an event you define. Each event comes with parameters that carry the detail: which page, which button, what value.
Data arrives through data streams. One property can hold a web stream together with iOS and Android app streams, so web and app users show up in the same report.
On the app side, measurement runs through Google Analytics in Firebase. App events such as screen views, sign-ups and purchases are planned with the same names as your web events; app installs and in-app conversions are tied to ad sources such as Google Ads, and the iOS permission prompt (ATT) is taken into account in the measurement design. We set this up and test it together with your developers as part of our Firebase and mobile measurement service.
Event types
| Type | How it is collected | Example |
|---|---|---|
| Automatically collected | On its own once the tag loads | first_visit, session_start |
| Enhanced measurement | Switched on or off in settings | Scrolls, outbound clicks, site search, file downloads |
| Recommended | Named by Google, set up by you | generate_lead, purchase, sign_up |
| Custom | Entirely your own definition | demo_request, price_calculator_use |
If a recommended event name exists, use it: GA4 recognizes these names and populates some reports based on them.
Key events and conversions
You mark the events that matter to your business as key events: a demo request for a B2B site, an appointment form for a clinic. In March 2024 Google renamed this flag, previously called "conversion", to key event. The term "conversion" now refers to actions shared with Google Ads and used in ad bidding strategies.
The practical meaning of this distinction: making an action a key event in GA4 does not mean it will be used for ad optimization. Which action counts as a conversion on the ads side is a separate decision.
Reports and explorations
GA4 has two kinds of analysis areas. Reports are ready-made summaries: acquisition, engagement, monetization, user attributes. Explorations are where you build your own analysis: funnel exploration, path exploration, segment comparison.
The detailed data used in explorations is kept only as long as the property's data retention setting; for standard properties that is at most 14 months. For longer-term analysis or raw data, use the BigQuery export.
BigQuery export
GA4 lets you export raw event data to Google BigQuery even from standard (free) properties. The daily export has an event count limit, which large sites should check. With the data in BigQuery you can combine ad costs, sales outcomes from your CRM and GA4 behavior in a single table. That combination is the first step toward a marketing data warehouse.
Setting up GA4: the right order
A good GA4 setup starts with a measurement plan, not with a tag. The order we recommend:
- Measurement plan. Which business question are you trying to answer? Which actions will be key events? Write each event's name and parameters into a table.
- Property and streams. Create the property with the right time zone and currency; add the web stream and any app streams.
- Consent management. Set up the cookie consent tool and Consent Mode before the tags. For details, see what is Consent Mode v2.
- Tags. Load the Google tag directly or through Google Tag Manager; set up custom events according to the plan.
- Settings. Extend data retention, filter internal traffic, define unwanted referrals (such as payment pages), and link Google Ads and Search Console.
- Validation. Test every event with DebugView and the realtime report; after a week, compare the numbers with your CRM or order data.
Common setup mistakes
- Making everything a key event. A scroll or a page view is not a key event; it muddies the report.
- Inconsistent event names.
form_send,formSubmitandform-submitcount as three separate events. - Sending personal data. Email addresses or phone numbers must not reach GA4 in URLs or parameters; this violates Google's policy.
- Leaving data retention at the default. The short default period limits how far back you can look in explorations.
- Skipping validation. If the number of leads in GA4 is very different from your CRM, something is wrong with the setup.
If you want your GA4 setup audited or built correctly from scratch, GA4 consulting is our entry product. The full measurement stack (tags, server-side tracking, reporting) is described on our data analytics consulting page.
Frequently asked questions
Is GA4 paid?
The standard version of Google Analytics 4 is free. For organizations that need higher data limits, a service level agreement and advanced features, there is the paid Google Analytics 360.
Where did my Universal Analytics data go?
Standard Universal Analytics properties stopped processing data on July 1, 2023, and Google later shut off access to the old properties. If you did not export the old data, you can no longer reach it in the interface; GA4 data starts from the date of its own setup.
What is the difference between a conversion and a key event?
In GA4, the events you mark as your important actions are now called key events. The term conversion is used for actions shared with Google Ads and used in ad optimization.
Is GA4 compliant with KVKK and GDPR?
Compliance depends more on your setup than on the tool: what data you collect, how you obtain cookie consent and what your privacy notice says. Consent management and Consent Mode must be set up correctly, no personal data should be sent, and the legal assessment should be done by an expert. (KVKK is Turkey's personal data protection law.)
Should I set up GA4 with Google Tag Manager?
For sites that use several tags, change things often or plan to move to server-side tracking later, Google Tag Manager is more flexible. For a simple one-page site, the Google tag installed directly may be enough.
Sources
Mahmud FiloğluManaging Partner
Co-founder of Roicool. Before founding Roicool, Mahmud had already worked with more than 15 clinics; today Mahmud leads the performance marketing, Google Ads, SEO and measurement work.
