Sampling plays a crucial role in extracting meaningful insights from large datasets, allowing for efficient analysis and decision-making. By creating sampling groups and adjusting rules, you can effectively focus on key areas for optimization to derive more accurate data.

By default, VWO tracks visitors who land on any page of your website with VWO SmartCode added. It means that the visitor becomes eligible for sampling in Insights. When a visitor becomes part of the random sample, VWO tracks their data for Goals, Funnels, Heatmaps, Recordings, and Form Analysis for the rest of their journey.

However, depending on your business requirements, you can also configure the sampling of your website visitors by keeping them specific to individual pages or a group of pages. VWO’s flexible sampling for Insights allows you to do this from the Sampling Groups section under Account Settings > More > Insights Settings. Thus, you can optimally collect insights data for your website.

NOTE: This feature is available for Pro and Enterprise plans.

Sampling Groups

• A Sampling Group represents a set of URLs to which you can apply a specific sampling rule. This allows you to distribute the sampling that is more appropriate to your situation.
• You can add up to 10 sampling groups, edit them for any changes or delete them if not required.
• Each sampling group has to be applied with one of the following sampling rules:

• The All Traffic sampling group with Dynamic Sampling (Default) is the default setting for every account. This means that all the web pages added with the SmartCode are enabled with dynamic sampling. You can neither remove this sampling group nor change its priority. However, you can configure its sampling rule.

Creating a Sampling Group

To create a sampling group, perform the following steps:

1. Click on the Add a group link.
2. In the Add a Sampling Group popup that appears, enter a name for the sampling group and configure the URLs of the pages to be included and excluded from the sampling group.

3. You can use the URL match conditions to define the URL patterns for the pages. You can add a maximum of 30 URLs for both including and excluding pages.
4. You can further configure the inclusion and the exclusion of the pages by clicking on the vertical ellipsis and selecting the following options as required:

5. With sampling pages configured, all visitors on those pages will be included appropriately by default. For specific segmentation (such as filtering visitors using location, promo referrals, etc.), tick the Select one or more segments checkbox.
6. You can either choose a standard segment from Standard Segments, a saved custom segment from My Segments or build one from scratch under Custom Segment. Refer to this article to learn about using segmentation in VWO.
7. Click Save.

Now, the sampling group is created. You can create multiple sampling groups and prioritize them as needed. 

Hover on the info icon on a sampling group to quickly view its configurations. Hover over the info icon along a URL criterion to view its URL configurations for each entry.

Prioritizing Your Sampling Groups

You can prioritize your sampling groups if there’s an overlap in their URLs. 

Check out this case - You’re looking to sample most of the visitors who arrive at your website through a marketing campaign for a few newly launched products while lowering the sampling rate on your products page. 

Now, if an unsampled visitor visits a URL that is included in both the sampling groups, then they will be sampled based on the sampling condition of the group at the top of the hierarchy. 

Let’s look at the following comparison:

Marketing Campaign First	Products Page First
The visitor gets a 95% chance to be sampled, otherwise excluded from sampling	The visitor gets a 30% chance to be sampled, otherwise excluded from sampling

To rearrange the sampling groups, simply click and hold this icon (⋮⋮) to drag a sampling group and drop it in the required position.

Use Case

By default, your account would consume visitors proportionately so that your quota lasts through the monthly billing cycle. 

Scenario: Suppose you recently launched a marketing campaign with an exclusive offer for a new product, for which you run advertisements on various social media platforms. You’re looking to track the behavior of your visitors who have arrived at your website by following your advertisement. 

Challenge: The default setting samples visitors dynamically and thereby will not fetch more sampled visitors for ProductX’s page. However, other product pages have significant traffic, whose behaviour is known to you.

Solution: To optimize quota usage, configure sampling rules that increase visitor sampling on ProductX's page while limiting it on other pages. This strategy allows tracking visitors as desired, capturing detailed behavior on the newly launched product without depleting the quota.

Additionally, you can refine your sampling by leveraging segmentation criteria. For example, if you want to measure the attraction of new visitors, you can set up a segment specifically targeting them.

Procedure:

1. On the Insights Settings page, click the Add a group link, create a sampling group for ProductX featuring its marketing campaign UTM parameter in the URL, tick the Select one or more segments checkbox to configure the visitors you want to sample and click Add.
   
2. Repeat the previous step to create another group for all other products already established in the market, as shown below and click Save.
   
3. For all the newly added sampling groups, VWO applies the Dynamic sampling rule. You can modify this to your preference. Since you need more attention towards ProductX, you shall apply a higher sampling rate to that group, say 95%. This means every visitor has a 95% chance to get sampled when they visit the pages included in the sampling group. Similarly, you can apply a lesser sampling rate to the established products for effective quota consumption. You can configure this value by selecting the Custom Sampling Rate option.
   
4. Once done, click Save.

Frequently Asked Questions

1. How will I be notified of my quota exhaustion?

When your quota exhaustion reaches 80%, the account owner and admins will be notified via email. The same happens when it reaches 100%, and in the VWO app, you will find a link to refresh your quota limit.

2. What will be the impact when all my quota is exhausted?

When your quota is completely exhausted, all your Insights campaigns, but for Surveys, will be paused and so will their respective data collection. They shall auto-resume when the quota is refreshed.

3. What happens if I have the same link under both Included pages and Excluded pages?

If the same URL is present on both Included pages and Excluded pages, any visitor to the page will not be sampled/ not samples for Insights as configured. VWO prioritizes the ones in the Excluded pages list over the ones in the Included pages. 

For example, if you add a site-wide URL pattern, say https://example.com*, in the Excluded pages, the Exclude settings are applied site-wide. As a result, no visitors are tracked even if you have listed specific page URLs under the Include section. VWO first checks for the Excluded pages settings and then checks for the Included pages settings.

4. A visitor lands on an excluded page and afterwards visits an included page during the journey. Will I be able to track the visitor’s referring URL?

VWO maintains a log of visitors' referrer and landing page URLs, regardless of whether they are eligible for sampling. For example, if a visitor lands on an excluded page and then happens to visit an included page during the journey, VWO will keep a record of the visitor’s referral website and the landing page. The visitor information can be used to track their behavior and interaction on the website after they are sampled for Insights.

5. What happens to the sampled visitors if I update my sampling rules?

Their data will continue to be captured, and new visitors will be sampled according to the updated rules.

6. If a visitor’s session gets sampled halfway through, what happens to their journey?

When a visitor’s session is sampled, the journey is tracked from that sampling point onward, capturing the interactions and events that occur after that moment.