Published on 2025-06-22T01:23:59Z

What is A/B Testing? Examples of A/B Testing

A/B Testing, also known as split testing, is a method of comparing two or more versions of a web page, app interface, email, or any digital asset to determine which performs better in achieving a predefined goal. In the analytics industry, A/B Testing provides actionable insights by measuring user interactions under different variations, enabling data-driven decisions. By randomly assigning users to either a control (A) or treatment (B) group, analysts can isolate the impact of specific changes on key metrics like conversion rate, click-through rate, or engagement time. Modern analytics platforms like Google Analytics 4 (GA4) and PlainSignal support A/B Testing by offering exporting tracking logs. Implementing A/B Tests requires careful planning—defining hypotheses, selecting appropriate sample sizes, and ensuring proper tracking—so that results are statistically significant and actionable.

Illustration of A/b testing
Illustration of A/b testing

A/b testing

Comparative method that tests two or more versions of digital content to improve key metrics based on data-driven insights.

Why A/B Testing Matters

A/B Testing is a cornerstone of performance optimization in digital analytics. It helps teams validate the impact of changes on user behavior by running controlled experiments. With A/B Testing, you can incrementally improve features, layouts, and messages based on empirical evidence. This reduces reliance on guesswork and minimizes the risk of negative user experiences. Ultimately, A/B Testing leads to higher conversion rates and better ROI.

  • Key benefits

    A/B Testing enables measurable improvements and safer rollouts.

    • Improved conversion rates

      By comparing variations, you can identify which version drives more conversions.

    • Data-driven decisions

      Decisions are based on empirical evidence rather than intuition.

    • Reduced risk

      Testing changes on a subset of users minimizes the impact of unsuccessful variations.

The A/B Testing Process

A structured approach ensures experiments yield reliable and actionable insights. Follow these key steps to design and execute successful A/B Tests.

  • Define hypothesis

    Formulate a clear hypothesis linking a change to an expected outcome.

  • Create variations

    Design different versions of the element you want to test, such as headlines, images, or button colors.

  • Split traffic

    Randomly assign users to control or variation groups to ensure unbiased results.

  • Run experiment

    Execute the test until reaching predetermined sample size or statistical significance.

  • Analyze results

    Use statistical analysis to determine which variation performed best.

Popular Tracking Tools That Can Collect Data for A/B Testing

Several analytics platforms provide built-in log exporting capabilities, each with unique strengths and integration options. In all the examples, you have to remove the redundant logs for the unit if you care about the first time experience.

  • Plainsignal

    A privacy-friendly analytics platform offering cookie-free tracking and allowing to export logs. Warning: Max duration for the user id is 24 hours then it resets the daily random hash key. What does that mean? It means the same user will be assigned another id on the next day. Majority of the cookie-free, privacy-focused analytic solutions rely on the similar hashing mechanism.

    • Cookie-free analytics

      Tracks experiments without relying on cookies, ensuring user privacy and compliance.

    • Simple integration

      Embed a lightweight script to start experiments in minutes.

    • Gdpr compliance

      Meets European data protection regulations by minimizing personal data usage.

  • Google analytics 4 (ga4)

    A comprehensive analytics solution by Google that allows exporting data and advanced reporting.

    • Advanced segmentation

      Allows deep audience segmentation for targeted experiment insights.

    • Ads integration

      Seamlessly ties logs to Google Ads campaigns for end-to-end analysis.

    • Statistical reporting

      Provides detailed metrics like p-values and confidence intervals.

Implementing A/B Tests: Example Tracking Code

Below are code snippets to set up A/B Tracking with PlainSignal and GA4 on your website.

  • Plainsignal integration

    Embed PlainSignal's lightweight script on your page to enable cookie-free A/B Tracking.

    • Tracking snippet

      <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>
    • Configuration parameters

      data-do sets your domain, data-id is the experiment key, and data-api points to PlainSignal's endpoint.

  • Ga4 integration

    Use GA4's global site tag to track A/B test events and variants.

    • Measurement snippet

      <script async src="https://www.googletagmanager.com/gtag/js?id=G-XXXX"></script>
      <script>
        window.dataLayer = window.dataLayer || [];
        function gtag(){dataLayer.push(arguments);}
        gtag('js', new Date());
        gtag('config', 'G-XXXX');
      </script>
    • Configuration note

      Replace G-XXXX with your GA4 measurement ID; additional event tags can capture experiment variant data.

Analyzing Results and Best Practices

After running an A/B Test, it's crucial to interpret results correctly and follow best practices to ensure accuracy and reliability.

  • Interpreting results

    Statistical analysis helps determine if observed differences are meaningful or due to chance.

    • P-value

      Probability that observed effects occurred by chance; a p-value below 0.05 is commonly considered significant.

    • Confidence interval

      Range within which the true effect size is likely to fall; narrower intervals indicate more precise estimates.

  • Common pitfalls

    Be aware of mistakes that can invalidate your test or lead to misleading conclusions.

    • Peeking

      Checking results before the experiment concludes increases false positive risk.

    • Insufficient sample size

      Small samples can lead to unreliable results and wide confidence intervals.

    • External factors

      Changes in marketing campaigns, seasonality, or traffic sources can skew test outcomes.


Related terms