Paid Media, Search, SEM

Using Custom Variables for Enhanced Conversion Measurement

This guide details the steps required to set up custom variable tracking in Search Ads 360, using Campaign Manager and Google Tag Manager. It also highlights several uses for custom variables, with instructions & screenshots for common cases.

Conversion measurement in paid search is great, but how can we collect information at a more granular level? Custom Floodlight Variables can provide hugely beneficial data to your Search Ads 360 accounts for reporting, optimisation, and strategic purposes.
By recording Floodlight data in the form of both dimensions & metrics, we can gain valuable insights into customer behaviour, product details and conversion attributes.

What Are Custom Variables?

Custom variables are useful across industry verticals; from simple eCommerce factors (e.g. payment method, coupon usage, currency) to product & user attributes (e.g. people per booking, lead purpose, education course type, new/returning customer). Collecting this data can help reveal the deeper value of advertising activity, provide client insights for future strategy, or simply allow for quicker and more efficient optimisation.

Google’s terms of use stipulate that no personally identifying information (PII) is recorded by the custom variable fields, meaning no email addresses, phone numbers, names, or similar.

The steps below assume familiarity with basic Floodlight tag creation, as well as knowledge regarding tag, trigger, and variable creation & mapping in GTM (if used).

Campaign Manager

The Fundamentals

Custom variables are handled at the base level by Google Campaign Manager (nee DoubleClick Campaign Manager). Here we create the Floodlight tags and their custom variable attributes, under the “Advertisers” section.

To set up your custom variables, navigate to the “Custom Floodlight variables” section on the “Floodlight configuration” tab. Here you can set up the variable/key (u1, u2, etc.) alongside a “friendly name” for reference, and a “Type”. The “Type” can be either a string (letters & numbers) or a metric (numbers only). For example, imagine we wish to track both the Course Name & Course Code for an Education client;

Keep in mind that while Campaign Manager can handle up to 100 custom variables, only u1 through u20 are available in Search Ads 360. If using Google Tag Manager, also ensure that your GTM container is linked to your Campaign Manager advertiser.

One you’ve saved your custom variable definitions, they need to be associated with a Floodlight activity. Navigate to the “Floodlight activities” section and select or create a Floodlight activity that will record these custom variables when triggering. Scroll to the bottom and tick the custom variables that you want that Floodlight to record, then save.

Google Tag Manager

The Path of Least Resistance

This guide uses Google Tag Manager (GTM) for tag implementation, which once placed on-site allows for tags & triggers to be created without needing direct access to the site’s code. If you’re not using GTM, the Floodlight can be inserted directly into the site’s code, using the variables on the page to populate the custom variables. GTM is recommended for ease of troubleshooting & variable management but is not the only option available.

Both Transaction and Counter tags are compatible with custom variables. When editing your Floodlight tag, click the “+ Custom Variable” button, and associate the desired GTM variable with the relevant custom variable key.

Once you’ve checked that the tag is collecting these variables correctly in Preview Mode, publish your container to the live site environment.

Search Ads 360

The Destination

First thing’s first: we need to define our custom variable within SA360 as either a dimension (i.e. a filter) or a metric (i.e. a count). Navigate to your advertiser’s “Advertiser Settings”, then click “Custom Floodlight Variables” under the “Floodlight” drop-down menu.

The Custom Floodlight Variables should appear here after syncing with Campaign Manager. The Type will be informed by the Campaign Manager type, which will be either a “String” which maps only to “Dimension”, or “Number” which maps to both “Dimension” and “Metric”.

If your variable is a number, you can change between “Dimension” & “Metric” types, however all historical data will be lost upon changing this setting (including changing to “Not Set”).

What Now?

Now our dimensions/metrics are available in Search Ads 360! So, what can we do with this new information?


The first and most obvious use is for reporting. Custom metrics can be easily added as columns for tracking and attribution, while dimensions can be filtered across campaigns/ad groups/keywords/ads. Custom dimensions cannot be used in conjunction with other dimensions, custom or standard.

To view all of the string results for a given dimension at once, you will need to be using either an “Action” or “Sales” view. Once you have selected the relevant view, you can choose your custom dimension from the “Dimensions” drop down menu to have a full view of all the string results for that date range. To see these results attributed to your search campaign attribution, tick the boxes next to the dimensions whose data you wish to view, and click “Filter to Selected”.

Another option is to create custom columns which identify specific custom variable values. In the case of our Education client, for example, we may wish to see how many enrolments “Business” courses have seen. To do this, we will create a new Floodlight column, and select the relevant Floodlight action that reports the custom variable. Then we will use the Custom dimension filter to specify courses that contain “Business” in the Couse Name variable.

Keep in mind that custom metrics & dimensions are also not compatible with cross-environment attribution, but can be used with last click, pre-defined & data driven attribution models across both reporting & bid strategies. Speaking of;


Bid Strategies

Custom dimensions can be used to define the difference in value between different conversion types. In our education example above, “Business” courses may be worth twice as much as “Health” courses; knowing this, we can create a bid strategy that weights our bids appropriate by first creating a formula column that weights the two course types appropriately (e.g. (2 * c:”business course”) + c:”health course”) and utilise this formula in a Target CPA strategy.

Unfortunately, custom metrics cannot be used in bid strategies. However, separate metrics can be defined via the custom dimensions.


Calculated Metrics

For example, an international travel company accepts purchases in a variety of different currencies, which are identified with a custom dimension, but want to estimate overall revenue in a single currency. These can be separated in the column creation by selecting the transaction Floodlight, defining the metric as Revenue, then using the Custom Dimension Filter to specify the string associated with a currency. After each currency has been separated, we can use a Formula Column to apply appropriate exchange rates to each and combine, resulting in a rough, consistent revenue that can even be used in a bid strategy.

Other Uses

Rules: For example, you can run a rule that automatically notifies you if a campaign with a high ratio of valuable lead types becomes limited by budget.

Custom data uploads: For advanced users, there’s the option of populating the custom variable data via the API. This is useful for any offline conversions that you may be tracking, including phone calls, store visits, or product returns. A full guide can be found here.

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