analytics · ga4-implementation

GA4 Implementation Reference

Detailed implementation guide for Google Analytics 4.

Configuration (data streams, enhanced measurement events, recommended events)
Custom Events (gtag.js implementation, Google Tag Manager)
Conversions Setup (creating conversions, conversion values)
Custom Dimensions and Metrics (when to use, setup steps, examples)
Audiences (creating audiences, audience examples)
Debugging (DebugView, real-time reports, common issues)
Data Quality (filters, cross-domain tracking, session settings)
Integration with Google Ads (linking, audience export)

Configuration

Data Streams

One stream per platform (web, iOS, Android)
Enable enhanced measurement for automatic tracking
Configure data retention (2 months default, 14 months max)
Enable Google Signals (for cross-device, if consented)

Enhanced Measurement Events (Automatic)

Event	Description	Configuration
page_view	Page loads	Automatic
scroll	90% scroll depth	Toggle on/off
outbound_click	Click to external domain	Automatic
site_search	Search query used	Configure parameter
video_engagement	YouTube video plays	Toggle on/off
file_download	PDF, docs, etc.	Configurable extensions

Recommended Events

Use Google's predefined events when possible for enhanced reporting:

All properties:

E-commerce:

view_item, view_item_list
add_to_cart, remove_from_cart
begin_checkout
add_payment_info
purchase, refund

Games:

level_up, unlock_achievement
post_score, spend_virtual_currency

Reference: https://support.google.com/analytics/answer/9267735

Custom Events

gtag.js Implementation

// Basic event
gtag('event', 'signup_completed', {
  'method': 'email',
  'plan': 'free'
});

// Event with value
gtag('event', 'purchase', {
  'transaction_id': 'T12345',
  'value': 99.99,
  'currency': 'USD',
  'items': [{
    'item_id': 'SKU123',
    'item_name': 'Product Name',
    'price': 99.99
  }]
});

// User properties
gtag('set', 'user_properties', {
  'user_type': 'premium',
  'plan_name': 'pro'
});

// User ID (for logged-in users)
gtag('config', 'GA_MEASUREMENT_ID', {
  'user_id': 'USER_ID'
});

Google Tag Manager (dataLayer)

// Custom event
dataLayer.push({
  'event': 'signup_completed',
  'method': 'email',
  'plan': 'free'
});

// Set user properties
dataLayer.push({
  'user_id': '12345',
  'user_type': 'premium'
});

// E-commerce purchase
dataLayer.push({
  'event': 'purchase',
  'ecommerce': {
    'transaction_id': 'T12345',
    'value': 99.99,
    'currency': 'USD',
    'items': [{
      'item_id': 'SKU123',
      'item_name': 'Product Name',
      'price': 99.99,
      'quantity': 1
    }]
  }
});

// Clear ecommerce before sending (best practice)
dataLayer.push({ ecommerce: null });
dataLayer.push({
  'event': 'view_item',
  'ecommerce': {
    // ...
  }
});

Conversions Setup

Creating Conversions

Collect the event - Ensure event is firing in GA4
Mark as conversion - Admin > Events > Mark as conversion
Set counting method:
- Once per session (leads, signups)
- Every event (purchases)
Import to Google Ads - For conversion-optimized bidding

Conversion Values

// Event with conversion value
gtag('event', 'purchase', {
  'value': 99.99,
  'currency': 'USD'
});

Or set default value in GA4 Admin when marking conversion.

Custom Dimensions and Metrics

When to Use

Custom dimensions:

Properties you want to segment/filter by
User attributes (plan type, industry)
Content attributes (author, category)

Custom metrics:

Numeric values to aggregate
Scores, counts, durations

Setup Steps

Admin > Data display > Custom definitions
Create dimension or metric
Choose scope:
- Event: Per event (content_type)
- User: Per user (account_type)
- Item: Per product (product_category)
Enter parameter name (must match event parameter)

Examples

Dimension	Scope	Parameter	Description
User Type	User	user_type	Free, trial, paid
Content Author	Event	author	Blog post author
Product Category	Item	item_category	E-commerce category

Audiences

Creating Audiences

Admin > Data display > Audiences

Use cases:

Remarketing audiences (export to Ads)
Segment analysis
Trigger-based events

Audience Examples

High-intent visitors:

Viewed pricing page
Did not convert
In last 7 days

Engaged users:

3+ sessions
Or 5+ minutes total engagement

Purchasers:

Purchase event
For exclusion or lookalike

Debugging

DebugView

Enable with:

URL parameter: ?debug_mode=true
Chrome extension: GA Debugger
gtag: 'debug_mode': true in config

View at: Reports > Configure > DebugView

Real-Time Reports

Check events within 30 minutes:
Reports > Real-time

Common Issues

Events not appearing:

Check DebugView first
Verify gtag/GTM firing
Check filter exclusions

Parameter values missing:

Custom dimension not created
Parameter name mismatch
Data still processing (24-48 hrs)

Conversions not recording:

Event not marked as conversion
Event name doesn't match
Counting method (once vs. every)

Data Quality

Filters

Admin > Data streams > [Stream] > Configure tag settings > Define internal traffic

Exclude:

Internal IP addresses
Developer traffic
Testing environments

Cross-Domain Tracking

For multiple domains sharing analytics:

Admin > Data streams > [Stream] > Configure tag settings
Configure your domains
List all domains that should share sessions

Session Settings

Admin > Data streams > [Stream] > Configure tag settings

Session timeout (default 30 min)
Engaged session duration (10 sec default)

Integration with Google Ads

Linking

Admin > Product links > Google Ads links
Enable auto-tagging in Google Ads
Import conversions in Google Ads

Audience Export

Audiences created in GA4 can be used in Google Ads for:

Remarketing campaigns
Customer match
Similar audiences