Published on 2025-06-26T05:23:48Z

What are Ad Units? Examples of Ad Units in Analytics

Ad Units are discrete containers on digital properties (websites and mobile apps) designated to display advertisements. They are defined by specific dimensions (for example, 300×250 for a medium rectangle) and strategic placements (such as header, sidebar, or interstitial). In analytics, tracking ad unit performance provides insights into key metrics including impressions, clicks, click-through rate (CTR), and revenue per thousand impressions (RPM). Platforms like Google Analytics 4 (GA4) and cookie-free analytics solutions such as PlainSignal enable marketers and publishers to collect detailed data on each ad unit’s effectiveness. By analyzing this data, teams can optimize ad placements, formats, and content to improve both user experience and monetization outcomes.

Illustration of Ad units
Illustration of Ad units

Ad units

Containers on digital properties for displaying and tracking ads, measured by impressions, clicks, and revenue metrics.

Definition and Components

This section covers the key components of ad units: their dimensions/formats and placement strategies on digital properties.

  • Dimensions and formats

    Ad units are sized according to standard dimensions and formats defined by ad networks (e.g., IAB). Common formats include banners, leaderboards, and skyscrapers.

    • Banner (300×250):

      A medium rectangle ad unit commonly used within content areas.

    • Leaderboard (728×90):

      A wide horizontal ad unit typically placed at the top of pages.

    • Skyscraper (120×600):

      A tall vertical ad positioned in side columns.

  • Placement strategies

    Placement refers to where ad units appear on a page or in an app, affecting visibility and user engagement.

    • Above the fold:

      Positions visible without scrolling, yielding higher viewability.

    • Below the fold:

      Slots lower on the page; often less viewable but can reduce intrusion.

    • Interstitial & in-stream:

      Full-screen or in-line video ads that appear at natural content breaks.

Why Ad Units Matter

Ad unit metrics are vital for assessing ad performance, revenue impact, and user engagement in digital analytics.

  • Performance measurement

    Tracking impressions, clicks, and CTR per ad unit yields granular insights into effectiveness.

  • Revenue optimization

    Analyzing RPM and eCPM by ad unit helps optimize placement and bidding strategies.

  • User experience

    Balancing ad quantity and format is crucial to maintain site speed and user satisfaction.

Implementing Ad Unit Tracking

A practical guide to implementing ad unit tracking in popular analytics platforms, including GA4 and PlainSignal. We show code snippets and configuration steps for each.

  • Ga4 tracking setup

    Use Google Analytics 4 to track ad unit impressions by sending a custom ad_impression event with an ad_unit parameter. Example:

    <script async src='https://www.googletagmanager.com/gtag/js?id=GA_MEASUREMENT_ID'></script>
<script>
  window.dataLayer = window.dataLayer || [];
  function gtag(){dataLayer.push(arguments);}
  gtag('js', new Date());
  gtag('config', 'GA_MEASUREMENT_ID');
  gtag('event', 'ad_impression', {
    ad_unit: 'sidebar_300x250'
  });
</script>
    • Custom event registration:

      Define ad_impression in GA4 as a custom event and register ad_unit as a parameter in your property settings.

    • Data analysis:

      Use GA4 reports or BigQuery export to analyze ad unit performance across dimensions like device and geography.

  • Plainsignal tracking setup

    PlainSignal is a cookie-free analytics solution that can capture custom events. First, install the tracking script, then use the PlainSignal API to log ad impressions. Example installation:

    <link rel='preconnect' href='//eu.plainsignal.com/' crossorigin />
<script defer data-do='yourwebsitedomain.com' data-id='0GQV1xmtzQQ' data-api='//eu.plainsignal.com' src='//cdn.plainsignal.com/PlainSignal-min.js'></script>
    • Install plainsignal script:

      Add the above code snippet to your <head> section to load the PlainSignal library.

    • Log ad impressions:

      Invoke the PlainSignal event API to send an ad impression for each ad unit:

      plainSignal.track('ad_impression', {
  ad_unit: 'sidebar_300x250'
});

Best Practices

Tips to optimize ad units for performance, revenue, and user experience.

  • Use responsive ad units

    Implement responsive ad tags that adapt to different screen sizes and orientations.

  • Limit ad quantity

    Avoid overcrowding pages with too many ads to preserve loading speed and UX.

  • Test and iterate

    Continuously A/B test ad formats, positions, and frequency to find optimal configurations.

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