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The Results page for Optimizely Web Personalization

  • Updated

Relevant products:

  • Optimizely Web Personalization

This topic describes how to:

  • Learn how Optimizely Web Personalization calculates results
  • Determine the definitions and formulas for result metrics

The Results page at a glance

The Results page allows you to track how well your campaigns perform. Dive into different experiences and audiences for a granular view of your visitors' behavior and take action.

Key tips

  • A session starts when a visitor lands on your site and ends after 30 minutes of inactivity. A new session is created if there's new activity.
  • By default, Personalization maintains a 5% holdback: we show 95% of visitors in a campaign a personalized experience, and holds back 5% who will see the original. 

What to watch out for

The Results page helps you track how well your campaigns perform. You'll use it to measure the success of each experience you deliver and explore your visitors' behavior.

Here are two ways to visit your Results page:

  • From the Experiments dashboard, click the Results button.
    persaonlization results

  • From the Manage Campaign dashboard, click View Results.

All results in Optimizely Web Personalization are in local time, according to the time zone set on your machine.

This article walks you through the Results page for Optimizely Web Personalization. Click to learn more about monitoring campaigns and taking action on results.

Jump down to learn about the key terms and metrics you see on your Results page. 

Campaign Summary

The Campaign Summary helps you track your campaign's overall impact. In the sidebar, you can view when the campaign was last published and the number of days it's been running.

Overall Improvement


The Overall Improvement module provides a high-level view of your campaign's progress.

By default, the module shows you the improvement in the campaign's primary metric with a confidence interval. The improvement measures the relative difference between personalized sessions and the holdback (original) experience. It also tells you about the reach of campaign reach: the number of personalized sessions delivered to visitors and the impact of that metric per session.

Use the dropdown to toggle between metrics that are attached to your campaign.


Or, use the calendar dropdown to select a different date range and click Apply.


Campaign Reach

The Campaign Reach module gives you a sense of how many personalized experiences were delivered, by session.


Page reach shows the total number of sessions that occurred on pages that were targeted by your campaign.

Audience reach shows the percentage of sessions that were delivered to one or more audiences in the campaign.

Personalized sessions show the number of sessions where a visitor saw a personalized experience. Holdback sessions show the number of sessions where a visitor saw the original experience because they're bucketed into the holdback by chance.

Experience Breakdown

The Experience Breakdown provides a visual summary of the impact of the campaign, broken down by audience.


The example above shows four audiences: "Existing Customers," "Media Vertical," "Strategic Accounts," and "High Tech Vertical." 

The width (x-axis) of each bar shows the reach of a particular audience. For example, the "Existing Customer" audience makes up 38.39% of total sessions in the campaign. All audiences in a campaign add up to 100%.

The height (y-axis) of each bar shows the change in conversion rate. The "Existing Customers" audience saw 20.99% lift in the primary metric, conversion rate, in this case. For conversion events such as clicks or pageviews, the y-axis shows the conversion rate. Revenue is displayed as revenue per visitor.

The color of the bars shows whether the change in conversion rate is statistically significant:

  • A green bar represents a statistically significant lift

  • A red bar represents a statistically significant loss

  • A gray bar represents a change that hasn't reached statistical significance

Learn about how Stats Engine calculates statistical significance.

To see more granular data about the primary metric by audience, click More Details.


The Impact column shows the difference in conversions in a personalized experience, compared to the holdback. It's broken down by audience.

Audience Summary

The Audience Summary helps you track the improvement generated by the personalized experience for each audience, broken down by metric.

Click to select an audience and view a summary.


Once you enter an audience summary, you can see how each metric performed for that audience.

The summary will always show your primary metric first (in the example below, the Requested Demoevent).


To view a graph of conversions in a specific metric for a particular audience, click View graph.


Segment results

Optimizely Web Personalization allows you to segment your results by attributes like browser, device, campaign, and source so you can drill down into the behavior of certain groups of visitors.

Segmenting your results gives you valuable insights about different groups of visitors, instead of simply analyzing the results across your entire visitor base. Figuring out what experiences work for different audiences can form the basis of a personalization strategy.

Metrics and definitions

Below are a few terms you'll see on your Results page. 

Metric Name




A session starts when a visitor lands on your site, continues as they navigate between pages, and ends after 30 minutes of inactivity—at which point the next visit creates a new session.

Absolute number

Personalized sessions

The number of sessions where a visitor was shown a personalized experience. This excludes visitors who either (1) don't qualify for any audience in the campaign or (2) qualify for an audience but are randomly bucketed into the holdback (control group).

Sum the treatment size overall Audiences


The percentage of total sessions that qualified for an audience (regardless of whether those visits were personalized).

Number of sessions for an audience / Total sessions


The number of sessions in which a visitor from any campaign audience converted on this event.

Absolute number

Conversion Rate

The percentage of sessions in which a visitor from any campaign audience converted on this event.

The number of sessions where conversions took place for that audience, or for total sessions.


Every Campaign has a “holdback,” which is like the control of an A/B test.

You can adjust the holdback for each campaign.

By default, Optimizely Web Personalization shows 95% of visitors in a campaign a personalized experience and holds back 5% who will see the original.

Confidence Interval

The confidence interval gives a range of values in which the conversion rate for a particular experience actually lies.

As you collect more data, the confidence interval will narrow. Once your variation reaches statistical significance, the confidence interval will always lie entirely above or below 0. 


The relative improvement of this event’s conversion rate for personalized sessions, compared to the holdback.

(Event Conversion Rate for Personalized visits - Event Conversion rate for Control visits) / (Event Conversion Rate for Control visits)

Improvements for an event for each audience

The % improvement in an Event’s conversion rate, comparing a personalized Audience to the control.

(Event Conversion Rate for Audience’s Personalized visits - Event Conversion rate for Audience control visits) / (Event Conversion Rate for Audience control visits)

Total Improvement in Primary Metric

The % improvement  of the Primary Metric across all sessions in the campaign (regardless of whether they fell into an audience).

(Conversion rate for sessions in the treatment - conversion rate of sessions in control) / conversion rate of sessions in control

Add or remove metrics

From the Results page, you can add or remove metrics from your campaign.

Existing events and tags are tracked all the time, so you can add them back if you want. However, if you add more than five events, it may take longer to reach statistical significance.

  1. Click Manage Metrics.

  2. Click the "+" to add metrics or drag metrics to remove them.

Set currency symbols

You can change the currency symbols displayed for revenue metrics via the Currency Picker that is located under the Advanced tab in the Project Settings:


Note that changing the currency symbol does not convert revenue values based on an exchange rate, it only changes the symbol displayed. So a revenue value displayed as $100.00 would become ¥100 after picking "¥", regardless of the current exchange rate between USD and JPY. Learn more about tracking revenue in Optimizely Web Personalization.

The currency symbol setting you select will be remembered for all sessions on your current browser. This means you will need to set the symbol again when logging in from a new device or browser.

How quickly do results update?

Results are typically available within 5 to 10 minutes of Optimizely Web Personalization receiving the data. Read our article about data freshness to learn more.

Reset or delete results

You can remove visitors and conversions from your Results page. 

On the Results page Campaign sidebar, click Reset Results.


At this time, clicking Reset Results will reset your results to the state of the last hourly refresh of your results. So even after you click reset you might see conversions and visitors who were part of your Campaign from this timeframe.