What Is Google Analytics (GA4)?
Abbreviation: GA4Also known as: GA4, Google Analytics 4
Google Analytics is a free platform, in its current GA4 version, that collects data from websites and apps to generate reports on visitor behaviour, traffic sources, and business performance.
Last reviewed: 3 August 2026 · Reviewed by iNet Ventures Analytics Team
In plain English
A small piece of tracking code placed on your site sends anonymised data to Google every time a visitor does something — loads a page, clicks a button, completes a purchase. GA4 processes this into reports showing where your traffic comes from, what people do once they arrive, and which of those actions actually matter to your business, defined as "key events."
Technical definition
GA4 is built entirely around an events-based data model, in contrast to its predecessor Universal Analytics' session-and-pageview model. Every interaction — a page load, a click, a purchase — is recorded as an event with associated parameters, sent to Analytics via the Google tag (gtag.js) or Google Tag Manager. Events fall into four categories: automatically collected (e.g. session_start), enhanced measurement (e.g. scroll, click, file_download, enabled without extra code), recommended (predefined names like purchase or sign_up that unlock built-in reporting), and custom (defined entirely by the site owner). Any event can be marked as a "key event" (GA4's replacement for Universal Analytics' "goals"), which — unlike UA's once-per-session goal counting — records every instance of the event, even multiple times in a single session.
Quick example
An ecommerce site marks its purchase event as a key event. GA4 then reports how many users completed a purchase, which marketing channel drove them, and how many total purchase events occurred — counting a user who buys twice in one session as two key events, unlike Universal Analytics which would have counted it once.
Quick facts
| Meaning | Google's free, event-based platform for measuring website and app performance |
|---|---|
| Main category | Analytics & measurement |
| Used by | Virtually every site owner and marketer measuring digital performance |
| Difficulty | Intermediate |
| Importance | Critical |
| Common examples | Traffic source reporting, conversion (key event) tracking, audience and engagement analysis, ecommerce reporting |
| Still relevant? | Yes — GA4 is now the only current version, since Google fully sunset Universal Analytics' standard properties in 2023. |
Why Google Analytics matters
GA4 is the standard tool for understanding what happens after a visitor arrives on your site — the piece Search Console alone doesn't cover.
It measures behaviour, not just Search visibility
Where Search Console shows how you appear in Google Search, GA4 shows what happens once someone actually lands on your site, across every traffic source — search, social, email, direct, and paid.
The events model is fundamentally different from Universal Analytics
Everything in GA4 is an event, including page views themselves. This is a genuinely different data model from Universal Analytics' sessions-and-pageviews structure, not just a rebrand.
Key event counting changed how conversions are measured
GA4 counts every instance of a key event, whereas Universal Analytics' goals counted a maximum of one conversion per session — a material difference that can make conversion counts look different between the two systems for the exact same underlying user behaviour.
It underpins attribution and channel reporting
GA4's traffic acquisition and channel reports are what most sites use to judge which marketing activities, including SEO and content, actually drive meaningful outcomes.
How it works
How data moves from a visitor's action to a GA4 report.
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1. The Google tag collects an interaction
When a user does something — loads a page, clicks a link, completes a purchase — the Google tag (via gtag.js or Tag Manager) captures it as an event with relevant parameters.
- 2
2. The event is sent and briefly visible in real time
The event appears almost immediately in the Realtime report, and DebugView (in debug mode) shows the specific parameters sent with it, useful for verifying implementation.
- 3
3. Analytics fully processes the event
Behind the scenes, GA4 aggregates and processes the raw event data into the dimensions and metrics used across standard reports, explorations, and audiences.
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4. Data surfaces in reports and audiences
Processed data becomes available in acquisition, engagement, monetisation, and retention reports, and can be used to build audiences for remarketing or further analysis.
Types and variations
The four categories of events GA4 recognises.
Automatically collected events
Collected by default with no setup required, such as session_start and first_visit.
Enhanced measurement events
Collected automatically once enhanced measurement is enabled in the GA4 interface, covering common interactions like scroll, click, and file_download.
Recommended events
Predefined event names and parameters for common business actions like purchase, login, or sign_up, which unlock existing and future built-in reports once implemented.
Custom events
Events defined entirely by the site owner for cases no other category covers. These don't appear in most standard reports and require custom reports or explorations to analyse.
Best practices
Set up GA4 deliberately, rather than accepting only what's automatically collected.
What to do
- Implement recommended events for standard actions (purchase, sign_up, login) to unlock built-in reporting rather than reinventing them as custom events
- Mark genuinely important actions as key events, and review which are marked periodically as the business evolves
- Use DebugView during implementation to verify events and parameters are firing correctly before relying on the data
- Exclude internal and developer traffic via filters so it doesn't distort real user data
- Use Google Tag Manager for easier long-term management of tagging changes without needing code deployments
What to avoid
- Assuming GA4 conversion counts are directly comparable to old Universal Analytics goal counts — the counting methodology genuinely differs
- Creating custom events for actions that already have a standard recommended event equivalent
- Excluding data you might want later — once data is processed and stored, exclusion filters applied afterward can't retroactively bring it back
- Relying solely on GA4 for Search-specific questions like query-level data — that's Search Console's job, not Analytics'
Common mistakes
Directly comparing GA4 and Universal Analytics numbers
GA4's key event counting (every instance) differs fundamentally from Universal Analytics' goal counting (once per session). The same underlying behaviour can produce different-looking numbers between the two systems, which isn't a data error.
Confusing GA4 with Google Search Console
GA4 measures on-site behaviour across all traffic sources. Search Console measures Search-specific visibility — queries, impressions, indexing. They answer different questions and should be used together, not interchangeably.
Placing event code above the Google tag snippet
Events added to a page above the main Google tag snippet won't be processed by GA4 — the tag must load first for subsequent event calls to be captured.
A genuinely different measurement model, not just a UI refresh
GA4's transition from Universal Analytics is frequently discussed as a redesign, but the underlying shift — from a fixed session-and-pageview model to a flexible, fully event-based one — changes how basically every metric should be interpreted. Teams that migrated dashboards or reporting expectations directly across from Universal Analytics without accounting for this often see numbers that look "wrong" when they are simply measuring something subtly different, particularly around conversion and session counting.
- Every interaction in GA4, including page views, is modelled as an event
- Key event counting (every instance) differs from Universal Analytics' once-per-session goal counting
- Universal Analytics standard properties were fully sunset by Google in 2023, making GA4 the only current option
- GA4 and Search Console are complementary tools measuring different things, not substitutes for each other
How iNet Ventures approaches google analytics
GA4 data is used alongside Search Console to give clients a complete picture of how link building and content work translates into actual site behaviour.
Full-funnel reporting
Traffic acquisition and key event data from GA4 is combined with Search Console visibility data to show clients the full path from earned visibility to genuine business outcomes.
Continue learning
Frequently asked questions
What is the difference between GA4 and Universal Analytics?
GA4 uses an entirely events-based data model where every interaction, including page views, is an event, whereas Universal Analytics used a session-and-pageview model with separate "goals" for conversions. GA4 also counts key events every time they occur, while Universal Analytics goals counted a maximum of once per session.
Is Google Analytics the same as Google Search Console?
No. GA4 measures on-site visitor behaviour across all traffic sources once someone arrives at your site. Search Console measures your visibility specifically within Google Search — queries, impressions, clicks, and indexing status. They are complementary tools.
What is a "key event" in GA4?
A key event is any event you've marked as particularly important to your business, GA4's replacement for Universal Analytics' "goals." Unlike goals, GA4 records every instance of a key event, even if it happens multiple times in one session.
Is Universal Analytics still available?
No, standard Universal Analytics properties stopped processing new data in July 2023. GA4 is now the only current version of Google Analytics.
Written directly from Google Analytics Help's official documentation on the GA4 events model and its comparison with Universal Analytics.
- Written by:
- iNet Ventures Editorial Team
- Reviewed by:
- iNet Ventures Analytics Team
- Published:
- 3 August 2026
- Last reviewed:
- 3 August 2026
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