User acquisition tells you where your new users come from — whether it's organic search, paid ads, email, or direct traffic. In GA4, this shifted from GA3's last-click model to data-driven attribution, which fundamentally changes how you measure channel performance. Understanding acquisition means knowing what marketing channels actually drive growth.
What User Acquisition Means in GA4
User acquisition is tracking where new users first arrive and what source/medium/campaign brought them in.
Understand the source, medium, campaign trio
GA4 attributes each new user to a source (where they came from: google, facebook, your-domain), medium (how they arrived: organic, cpc, referral), and campaign (which specific campaign, if tagged). These dimensions form the core of acquisition analysis. View them in Reports > Acquisition > Traffic acquisition.
// Query user acquisition dimensions via GA4 Data API
const request = {
property: 'properties/YOUR_GA4_PROPERTY_ID',
dateRanges: [{
startDate: '2024-01-01',
endDate: '2024-01-31'
}],
dimensions: [
{ name: 'firstUserSource' },
{ name: 'firstUserMedium' },
{ name: 'firstUserCampaignName' }
],
metrics: [
{ name: 'newUsers' },
{ name: 'userConversionRate' }
]
};
// Returns new users grouped by their original acquisition sourceKnow that GA4 uses data-driven attribution by default
Unlike old Google Analytics, GA4 doesn't rely on last-click attribution. Instead, it analyzes user journeys and credits the touchpoints that actually influenced conversions. You can't disable this entirely, but you can switch to first-click or last-click models in Admin > Data display > Attribution settings if needed for legacy reporting.
Setting Up Acquisition Tracking
Proper acquisition tracking requires tagging URLs with UTM parameters and ensuring GA4 sees the full URL.
Tag campaign URLs with UTM parameters
Add utm_source, utm_medium, and utm_campaign to any URL you share in ads, email, or social. For example: https://yoursite.com?utm_source=facebook&utm_medium=paid_social&utm_campaign=winter_sale. GA4 parses these automatically and categorizes the user under Facebook / Paid Social / Winter Sale. No additional code required — just use the URL.
// Example URL structure with UTM parameters
const campaignUrl = `https://yoursite.com?utm_source=facebook&utm_medium=paid_social&utm_campaign=winter_sale&utm_content=hero_image&utm_term=shoes`;
// GA4's gtag.js automatically parses UTM params from the URL
// No SDK code needed — just send users to this URL
// If you need to manually override acquisition data:
gtag('event', 'page_view', {
'campaign_source': 'facebook',
'campaign_medium': 'paid_social',
'campaign_name': 'winter_sale'
});Ensure your data stream captures full URLs
In Admin > Data streams > [Your stream], make sure GA4 is collecting the full page URL, including query parameters. If your redirects or server-side code strips UTM parameters, GA4 will see the traffic as Direct instead of your intended source. Audit your redirect chains in your web server logs.
Keep UTM naming consistent
Always lowercase your UTM values. If you tag one campaign as Winter_Sale and another as winter-sale, GA4 treats them as separate campaigns. Create a UTM naming convention and stick to it across all teams (marketing, growth, product).
Reading Acquisition Reports
Once tracking is set up, GA4 shows you where users are coming from via built-in acquisition reports.
View your top acquisition channels
Go to Reports > Acquisition > Traffic acquisition. This shows all new users grouped by source and medium. By default it shows active users, but switch the metric to new users to focus on actual acquisition. Click any source to drill down and see which specific campaigns performed best.
// Pull top acquisition channels via GA4 Data API
const acquisitionReport = {
property: 'properties/YOUR_GA4_PROPERTY_ID',
dateRanges: [{
startDate: '2024-01-01',
endDate: '2024-01-31'
}],
dimensions: [
{ name: 'firstUserDefaultChannelGroup' } // Organic, Paid Search, Direct, etc.
],
metrics: [
{ name: 'newUsers' },
{ name: 'userConversionRate' }
],
orderBys: [
{ metric: { metricName: 'newUsers' }, desc: true }
]
};
// Returns new users by default channel group, ordered by volumeCompare campaign performance
Use Acquisition > Campaigns to compare individual campaigns head-to-head. See which campaign — winter_sale vs. summer_promotion — brought in more users and generated better conversion rates. This is where you find what actually works.
Identify your best-quality acquisition sources
Don't optimize for user volume alone. Compare new users, conversion rate, and average purchase value by source. Organic might bring more users, but paid search might have 3x the conversion rate. Quality matters more than quantity.
Common Pitfalls
- Analyzing active users instead of new users when studying acquisition. Active users include returning visitors, which masks the fact that your acquisition channels are struggling. Always filter for new users when measuring acquisition performance.
- Inconsistent UTM tagging. If you tag 50% of campaigns and skip UTM on the rest, untagged traffic gets attributed to Direct, hiding your true channel mix and ROI.
- Assuming GA4's data-driven attribution matches your ad platform's numbers. GA4 and Facebook and Google Ads use different attribution models. Numbers rarely match exactly, and that's expected.
- Forgetting that first-user dimensions are immutable. Once GA4 assigns a user to Facebook as their source, that never changes, even if they return via email or direct. Use first-user dimensions, not all-time dimensions, for acquisition analysis.
Wrapping Up
User acquisition in GA4 is about understanding where new users come from: their source, medium, and campaign. Tag your marketing URLs with UTM parameters, check your acquisition reports regularly, and optimize for user quality, not just volume. If you want to track this automatically across tools, Product Analyst can help.