How to calculate the size of your website pool

Ensuring that visitors see a unique number from the website pool placed on your site is crucial to the validity of your data. For this reason, your website pool needs to contain enough numbers to cover all of your site’s visitors that you’d like to track. The amount of numbers is set during website pool creation but can also be adjusted for any existing pool.

For instructions on creating a new website pool, see this help article.

What does misattributed data look like?

If your website pool is too small and two visitors see the same tracking number, misattribution occurs – the information acquired on one visitor may be applied erroneously to the other. If you're reviewing a lead's timeline and find that your visitor's history isn't quite making sense, your website pool may be too small.

For instance, if your pool is too small, two of your website visitors might see the same phone number on your website. As they separately navigate your site, because they're both seeing the same phone number, we'd combine their separate sessions under the person who contacts you first. This can misrepresent visitors’ session browsing data and lead to false impressions on how they are interacting with your site, including their visit history. 

More broadly, your pool is set to track all visitors regardless of source, you may see instances such as a visitor coming through an ad being labeled as coming to your site directly, which would affect conversions in your ad platform. 

Assessing website pool size by measuring site visitors

By using Google Analytics to view your site’s traffic, you can use the following rule to decide how many numbers should be in your pool:

The number of peak hourly visitors divided by four equals the size of your pool.

For instance, if your highest number of simultaneous visitors is 100, your pool would be 25. This is meant to cover all traffic situations your site sees, hence basing it off the maximum number of visitors it receives at once.

While the rule above covers many usage instances, your business’s needs may vary. For instance, while we generally recommend charting hourly visitors over the previous two weeks, a seasonal business may be better served by charting their peak season instead. 

Note: Four is the minimum amount of numbers that can be in a given pool. Lower amounts have been found to negatively impact attribution quality.

Viewing your site traffic in Google Analytics

Log in to Google Analytics and use the following steps to find your pool number.

  1. Choose Explore from the left menu.

  2. Choose Blank from the reporting options.

  3. In the Segments field, choose None.

  4. Under Visualizations, choose Line chart.

  5. In the Granularity field, choose Hour.

  6. In the Dimensions field, choose Date + hour.

  7. In the Metrics field, choose Sessions.

  8. In the Values field, choose Sessions.


  9. Chart your traffic hourly for the past two weeks.

  10. Find and click on your peak hour and divide that number by four. This will give you an idea of how many numbers you need.

How to adjust the size of an existing website pool

Your website pool can always be adjusted to accommodate changes to traffic. You can use the support articles below to help you increase or decrease the size of your website pool.

Increase the size of a website pool.

Decrease the size of a website pool.

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