Google Analytics 4 Complete Guide

Overview

Google Analytics 4 (GA4) is Google's event-based analytics platform for measuring user interactions across websites and applications. This comprehensive skill provides guidance on all aspects of GA4 - from initial property setup through advanced analysis, implementation methods, and compliance.

GA4 uses an event-based data model where every user interaction is tracked as an event with associated parameters. This differs from the session-based model of Universal Analytics, providing more flexibility and cross-platform measurement capabilities.

When to Use This Skill

Invoke this skill for any GA4-related task, including:

Setup and Configuration:

• Creating GA4 properties and data streams
• Configuring Measurement IDs (G-XXXXXXXXXX)
• Setting up data retention and collection settings
• Managing property access and permissions

Implementation:

• Installing GA4 via gtag.js, GTM, or CMS plugins
• Implementing event tracking (automatic, recommended, custom)
• Setting up ecommerce tracking
• Configuring cross-domain measurement

Events and Tracking:

• Understanding event architecture and parameters
• Implementing recommended events (purchase, login, sign_up)
• Creating custom events for business-specific tracking
• Working with event parameters and limits

Analysis and Reporting:

• Using standard reports and Explorations
• Building funnel and path analyses
• Creating audiences and segments
• Exporting data to BigQuery

Advanced Topics:

• Measurement Protocol for server-side tracking
• User ID and cross-device tracking
• Privacy compliance and Consent Mode
• DebugView testing and validation

Quick Start

1. Create GA4 Property

1. Navigate to analytics.google.com
2. Admin -> Create -> Property
3. Enter property name, timezone, currency
4. Create web data stream
5. Note your Measurement ID (G-XXXXXXXXXX)

2. Install Tracking (Choose One Method)

Option A: Google Tag Manager (Recommended)

1. Install GTM container on website
2. Create Google Tag with GA4 Measurement ID
3. Trigger: Initialisation - All Pages
4. Publish container

Option B: gtag.js Direct

<script async src="https://www.googletagmanager.com/gtag/js?id=G-XXXXXXXXXX"></script>
<script>
  window.dataLayer = window.dataLayer || [];
  function gtag(){dataLayer.push(arguments);}
  gtag('js', new Date());
  gtag('config', 'G-XXXXXXXXXX');
</script>

3. Verify Installation

1. Enable Google Analytics Debugger extension
2. Admin -> DebugView
3. Confirm events appearing: session_start, page_view
4. Check Realtime reports for active users

4. Send Custom Events

gtag('event', 'button_click', {
  'button_name': 'Subscribe',
  'button_location': 'header'
});

Decision Tree: Which Reference Do I Need?

What are you trying to do?

Setting up GA4 for the first time?
  -> references/setup.md

Understanding how events work?
  -> references/events-fundamentals.md

Implementing standard tracking events?
  -> references/recommended-events.md

Creating business-specific custom events?
  -> references/custom-events.md

Making parameters appear in reports?
  -> references/custom-dimensions.md

Implementing User ID / cross-device tracking?
  -> references/user-tracking.md

Building audiences for remarketing?
  -> references/audiences.md

Analysing data in GA4 reports?
  -> references/reporting.md

Exporting to BigQuery for SQL analysis?
  -> references/bigquery.md

Installing via gtag.js directly?
  -> references/gtag.md

Setting up GA4 in Google Tag Manager?
  -> references/gtm-integration.md

Sending events from server/backend?
  -> references/measurement-protocol.md

Testing and debugging implementation?
  -> references/debugview.md

Implementing GDPR/Consent Mode?
  -> references/privacy.md

Configuring Admin settings?
  -> references/data-management.md

Core Concepts

Event-Based Model

GA4 tracks everything as events. Four categories:

Category	Description	Examples
Automatic	Fire without configuration	session_start, first_visit
Enhanced Measurement	Toggle on/off in settings	scroll, click, file_download
Recommended	Google-defined with standard parameters	purchase, login, sign_up
Custom	Business-specific tracking	demo_requested, trial_started

Key Limits and Constraints

Limit	Value
Event names per property	500 distinct
Parameters per event	25
Event name length	40 characters
Parameter name length	40 characters
Parameter value length	100 characters
Custom dimensions (event-scoped)	50
Custom dimensions (user-scoped)	25
Custom dimensions (item-scoped)	10
Audiences per property	100

Measurement ID Format

• Format: G-XXXXXXXXXX (G- prefix + 10 alphanumeric characters)
• Location: Admin -> Data Streams -> Web Stream
• Used in: gtag.js config, GTM tags, Measurement Protocol

Topic Overview

Setup and Installation

Reference: references/setup.md

Create GA4 accounts, properties, and data streams. Covers account hierarchy, property configuration, data stream setup for web/iOS/Android, and initial configuration settings.

Events Fundamentals

Reference: references/events-fundamentals.md

Understand GA4's event-based architecture. Covers the four event categories, event structure, parameter scopes (event/user/item), naming conventions, and limits.

Custom Events

Reference: references/custom-events.md

Create business-specific events beyond recommended events. Covers naming conventions, parameter design, industry patterns (SaaS, education, media), and implementation examples.

Recommended Events

Reference: references/recommended-events.md

Implement Google-defined recommended events. Covers engagement events (login, sign_up), monetisation events (purchase, add_to_cart), and the items array structure for ecommerce.

Custom Dimensions

Reference: references/custom-dimensions.md

Transform event parameters into reportable dimensions. Covers registration workflow, scope selection (event/user/item), custom metrics, calculated metrics, and troubleshooting.

User Tracking

Reference: references/user-tracking.md

Implement User ID and cross-device tracking. Covers User ID setup, user properties, Reporting Identity options, cross-domain tracking, and data deletion.

Audiences

Reference: references/audiences.md

Create segments for analysis and remarketing. Covers audience conditions, predictive audiences, sequence conditions, membership duration, and Google Ads export.

Reporting

Reference: references/reporting.md

Analyse data using standard reports and Explorations. Covers report types, exploration techniques (funnel, path, cohort), segments, comparisons, and attribution models.

BigQuery Export

Reference: references/bigquery.md

Export raw event data to BigQuery for advanced analysis. Covers linking setup, table schema, SQL query patterns, UNNEST operations, and cost optimisation.

gtag.js Implementation

Reference: references/gtag.md

Implement GA4 directly using gtag.js without GTM. Covers installation, gtag commands (config, event, set), common patterns, and framework integration.

GTM Integration

Reference: references/gtm-integration.md

Implement GA4 using Google Tag Manager. Covers configuration tags, event tags, triggers, variables, data layer integration, and Preview mode testing.

Measurement Protocol

Reference: references/measurement-protocol.md

Send events server-side using the Measurement Protocol API. Covers authentication, request format, validation, Python/Node.js/PHP examples, and best practices.

DebugView

Reference: references/debugview.md

Test and validate GA4 implementation. Covers enabling debug mode, reading DebugView interface, validation workflows, and troubleshooting common issues.

Privacy Compliance

Reference: references/privacy.md

Implement GDPR/CCPA compliance. Covers Consent Mode v2, consent parameters, regional settings, data deletion, and integration with consent management platforms.

Data Management

Reference: references/data-management.md

Configure GA4 Admin settings. Covers data retention, data filters, user permissions, property settings, enhanced measurement, and key events (conversions).

Common Workflows

Implementing Ecommerce Tracking

1. Review recommended events: references/recommended-events.md
2. Implement the purchase funnel:
   • view_item -> add_to_cart -> begin_checkout -> purchase
3. Structure items array correctly:
   • Required: item_id OR item_name
   • Recommended: price, quantity, item_category
4. Test with DebugView: references/debugview.md
5. Register custom item parameters: references/custom-dimensions.md

Setting Up Cross-Device Tracking

1. Implement User ID: references/user-tracking.md
2. Configure Reporting Identity: Admin -> Data Settings -> Reporting Identity
3. Set user properties: references/custom-dimensions.md
4. Build cross-device audiences: references/audiences.md

Implementing GDPR Compliance

1. Set up Consent Mode: references/privacy.md
2. Configure default consent state (denied)
3. Integrate with CMP (OneTrust, Cookiebot, etc.)
4. Update consent on user acceptance
5. Test consent implementation: references/debugview.md

Building Custom Reports

1. Understand available data: references/reporting.md
2. Register custom parameters as dimensions: references/custom-dimensions.md
3. Create Explorations for custom analysis
4. For unsampled data, export to BigQuery: references/bigquery.md

Best Practices

Naming Conventions

• Use snake_case for event names: video_tutorial_watched
• Be descriptive and action-oriented
• Keep under 40 characters
• Avoid generic names (event1, click, data)

Implementation Strategy

1. Start with Enhanced Measurement (automatic events)
2. Add recommended events for standard tracking
3. Create custom events only when needed
4. Register parameters as custom dimensions for reporting
5. Test thoroughly with DebugView before production

Data Quality

• Create separate properties for test/production
• Set up internal traffic filters from day one
• Document all custom events and parameters
• Regularly audit implementation with DebugView
• Export to BigQuery for data backup

References

Topic	File
Property Setup	references/setup.md
Events Fundamentals	references/events-fundamentals.md
Custom Events	references/custom-events.md
Recommended Events	references/recommended-events.md
Custom Dimensions	references/custom-dimensions.md
User Tracking	references/user-tracking.md
Audiences	references/audiences.md
Reporting	references/reporting.md
BigQuery Export	references/bigquery.md
gtag.js Implementation	references/gtag.md
GTM Integration	references/gtm-integration.md
Measurement Protocol	references/measurement-protocol.md
DebugView Testing	references/debugview.md
Privacy Compliance	references/privacy.md
Data Management	references/data-management.md