How to Map Cross-Device Customer Journeys

In the modern Australian digital landscape, your customers don't just find you and buy from you in a single sitting. They might find your Brisbane-based business on their mobile while commuting on the Translink, research your services on a tablet at home, and finally make a purchase on their office desktop. If you aren't mapping these cross-device journeys, you are likely misattributing your sales and undervalueing your top-of-funnel marketing efforts.

Understanding the cross-device journey allows you to see the "big picture," ensuring you don't cut budget from a mobile ad campaign that looks like it's underperforming but is actually the primary discovery source for your highest-paying clients.

Prerequisites: What You’ll Need

• Google Analytics 4 (GA4) Account: You must be using GA4 (the standard since July 2023).
• Editor or Administrator Access: You need permission to change property settings.
• A Website with User Login (Optional but Recommended): While GA4 uses several signals, having a User ID system is the gold standard for accuracy.
• Privacy Policy: Ensure your website's privacy policy is updated to disclose that you use tracking technologies (standard for Australian businesses under the Privacy Act).

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Step 1: Understand the Three Identity Spaces

• User ID: The most accurate. If a user logs into your site on different devices, they are assigned a unique ID.
• Google Signals: Data from users who are signed into their Google accounts and have turned on Ad Personalization.
• Device ID: The least accurate. This uses the browser cookie or mobile app instance ID.

Step 2: Activate Google Signals

• Log in to your GA4 property.
• Click Admin (the cog icon in the bottom left).
• Under the Property column, click Data Settings > Data Collection.
• Locate the "Enable Google signals data collection" section and click Get Started.
• Follow the prompts to activate it.

Step 3: Set Your Reporting Identity

• In the Admin menu, go to Property Settings > Reporting Identity.
• Select Blended. This tells Google to look for User ID first, then Google Signals, then Device ID to stitch the journey together.
• Click Save.

Step 4: Implement User ID Tracking (For E-commerce/Portals)

• Work with your developer to push the User ID into the dataLayer when a user logs in.
• In Google Tag Manager, update your GA4 Configuration tag to include a field called user_id.
• Map this field to the variable capturing your site’s internal User ID.

Step 5: Access the Path Exploration Report

• Navigate to the Explore tab in the left-hand sidebar.
• Select Path Exploration (the blank template is also fine, but Path Exploration is built for this).
• In the "Node Type" dropdown, select Device Category.

Step 6: Visualise the Device Switch

• Set the starting point as a "Session Start."
• Add a step for "Device Category."
• Look for patterns where users start on "Mobile" and eventually convert on "Desktop."

Step 7: Analyse the "Segment Overlap" Report

• Create a new Segment Overlap exploration.
• Create three segments: "Mobile Users," "Tablet Users," and "Desktop Users."
• Drag all three into the "Segment Comparisons" area.

Step 8: Review Attribution Models

• Go to Admin > Data Settings > Attribution Settings.
• Ensure Data-driven attribution is selected. Unlike "Last Click," this model uses Google's AI to give credit to every device touchpoint in the journey.

Step 9: Use the Tech Details Report

• Go to Reports > Tech > Tech details.
• Change the primary dimension to Device Category.
• Compare the conversion rate of Mobile vs. Desktop. If Mobile has a high traffic volume but a 0% conversion rate, use your cross-device mapping to see if those people are just finishing the purchase on Desktop later.

Step 10: Set Up Cross-Device Audiences for Remarketing

• Go to Admin > Audiences.
• Create a new audience (e.g., "Mobile Visitors - Non-Converters").
• Because Google Signals is on, when you link GA4 to Google Ads, your desktop ads will reach these mobile users seamlessly.

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Pro Tips for Australian Marketers

• Consider the "After Hours" Effect: Many Australians browse for services (like plumbers or dentists) on mobile during their commute or while watching TV, but wait until they are at a desk to fill out complex forms. Don't stop your mobile ads at 5 PM!
• Check for "Session Stitching": If your site has a sub-domain (e.g., shop.yourbusiness.com.au), ensure cross-domain tracking is set up, or the cross-device journey will break when they move between sections of your site.

Common Mistakes to Avoid

• Ignoring the Thresholding: If your site has low traffic, Google may "threshold" (hide) some data in reports to protect user privacy when Google Signals is active. If you see little warning icons in your reports, this is why.
• Not Updating Privacy Policies: Under Australian law, if you use Google Signals, you must inform your users. Failing to do so can lead to compliance issues.

Troubleshooting

• Data looks the same after turning on Signals: It can take 24–48 hours for Google to begin stitching data together. Check back in a few days.
• Users appearing as "Unset": This usually happens if the tracking code isn't firing correctly on all pages. Ensure your GA4 tag is present on every page of your site.
• High "Direct" traffic: This often means the cross-device link is broken. Check that your User ID implementation is firing on the very first page load after login.

Next Steps

If you find the technical setup of GA4 and User ID tracking a bit overwhelming, the team at Local Marketing Group is here to help. We specialise in helping Brisbane businesses make sense of their data to drive real-world results.