Published on 2025-06-28T08:32:04Z

What is First Interaction in Analytics? Examples with GA4 and PlainSignal

First Interaction, also known as first-touch attribution, identifies the very first point of contact between a user and your site or app. In analytics, it assigns full credit for a conversion to this initial touchpoint, providing insight into which channels are most effective at raising awareness. This model is especially useful for marketing teams focusing on top-of-funnel activities and understanding how users first discover their brand. Tools like Google Analytics 4 (GA4) automatically capture first interaction data under acquisition reports, while privacy-centric platforms like PlainSignal offer simple, cookie-free tracking of entry events. By analyzing first interaction metrics, businesses can optimize initial engagement strategies, allocate budgets more effectively, and refine campaign targeting. However, relying solely on first interaction can overlook the influence of subsequent touchpoints, so it should be used alongside other attribution models for a comprehensive view.

Illustration of First interaction
Illustration of First interaction

First interaction

Initial touchpoint attribution model crediting the first user interaction for conversions in analytics.

Definition and Importance

First Interaction attribution assigns full conversion credit to the user’s initial engagement with your site or app. This model highlights which channels—such as organic search, paid ads, or referrals—drive the earliest interactions. By focusing on first touchpoints, marketers can understand and optimize top-of-funnel performance. While insightful, this model doesn’t account for later touchpoints, so it’s often combined with other attribution approaches.

  • What is first interaction

    The very first point of contact between a user and a website or app, such as an initial pageview, click, or event.

  • Why it matters

    It reveals which channels initiate user engagement, informing top-of-funnel marketing decisions and budget allocation.

How First Interaction Attribution Works

In First Interaction attribution, only the earliest touchpoint in a user’s journey receives credit for any subsequent conversion. This approach simplifies analysis by isolating the initial source but may overlook the contributions of later engagements. It helps identify the most effective awareness channels, although it should be used in conjunction with other models for holistic insights.

  • Identification of the initial touchpoint

    Analytics platforms detect the first recorded interaction event for each user session, such as a pageview or click.

    • Session tracking:

      Cookies or session IDs link user actions over time to determine the first event.

    • Source/medium detection:

      Captures marketing parameters like UTM tags to classify the origin.

  • Credit assignment

    All conversion credit is attributed to the identified first interaction, regardless of subsequent touchpoints.

    • Conversion tracking:

      Events like purchases or sign-ups are linked back to the first touchpoint.

    • Model accuracy:

      Less precise if initial touch data is incomplete or privacy restrictions apply.

First Interaction in GA4

Google Analytics 4 provides built-in first interaction attribution within its acquisition reports. GA4 labels it as ‘first user source’ in key reports and integrates across the platform.

  • Ga4 attribution model settings

    GA4 offers configurable attribution models, including first interaction, under Attribution Settings in Admin. Users can select ‘First user’ to view first interaction reports.

  • Key reports

    The ‘User acquisition’ and ‘Traffic acquisition’ reports display first user source/medium metrics, helping you analyze where new users originate.

First Interaction with PlainSignal

PlainSignal is a simple, cookie-free analytics platform that tracks first interactions with minimal setup. It focuses on privacy, using cookieless methods to detect entry events.

  • Integration example

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<script defer data-do="yourwebsitedomain.com" data-id="0GQV1xmtzQQ" data-api="//eu.plainsignal.com" src="//cdn.plainsignal.com/PlainSignal-min.js"></script>

  • Analyzing first interaction

    In PlainSignal’s dashboard, navigate to the ‘Acquisition’ section to view entry events grouped by referrer, landing page, and campaign parameters.

Best Practices for First Interaction Attribution

To maximize the value of first interaction data, combine it with other models, ensure accurate tagging, and regularly audit your attribution setup.

  • Combine with multi-touch attribution

    Use first interaction alongside models like last interaction or linear attribution for a fuller view of the customer journey.

  • Implement consistent utm parameters

    Standardize UTM tagging across campaigns to ensure accurate source/medium detection for first interactions.

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