Understand your Conversion Lift based on users measurement data

In this article, we explain the meaning of metrics within your study and users-based Conversion Lift reporting.

How do we measure lift?

Conversion Lift based on users measures the causal, incremental impact of your campaigns by measuring conversions from users who saw ads in the treatment group and users who were held back from seeing ads in the control group. Cumulative results may be available during the study, but we recommend waiting until the end of your study to get the most accurate lift results.

Conversion Lift based on users metrics and statuses

Here’s how you check your Conversion Lift based on users data:

In your Google Ads account, click the Goals icon .
Click the Measurements drop down in the section menu.
Click Lift measurement.
Here you can view incremental conversions and Relative Lift for all biddable conversions in table view, alongside campaign impressions, cost, and Brand or Search Lift metrics.
Click on the study name to view detailed study results.

Metrics

Conversion metrics

Incremental conversions

Incremental conversions = Treatment conversions - Control conversions

The “Incremental conversions” metric, also known as "Absolute Lift," reflects the incremental conversions you were able to generate due to your ad campaigns over the duration of the study. In other words, the conversions wouldn't have happened without the campaigns. It’s computed as the difference between the treatment and control conversions.

Understanding Incremental conversions and Attributed conversions

It’s important to understand the differences between Incremental conversions, measured by Conversion Lift, and the standard attributed conversions displayed in Google Ads reporting.

Standard attributed conversions: These are the conversions reported within your Google Ads campaigns. They are counted based on the specific conversion tracking settings and attribution rules configured for each conversion action. For example, these settings may include click or view-based attribution windows (e.g., a 7-day click-through window).
Incremental Conversions (Conversion Lift): Also known as “incrementality,” Conversion Lift measures the true causal impact of your advertising. It quantifies how many additional conversions occurred because users saw your ads, which wouldn’t have happened otherwise. Unlike standard reporting, Conversion Lift intentionally ignores the standard conversion tracking settings and attribution rules. Instead, it measures the difference in all conversions between an experiment group (which saw the ads) and the control group (which did not) over the full study duration.

While standard reporting attributes conversions based on your predefined settings, Conversion Lift counts separately the net new conversions directly driven by your ad exposure.

Incremental cost per action

Incremental cost per action = Total ad spend / Incremental conversions

The Incremental cost-per-action (iCPA) metric reflects the cost to acquire one incremental conversion that was driven by your ads. For example, if you spent $10,000 on a campaign, and the Conversion Lift study shows your campaigns drove 800 incremental conversions, your incremental CPA would be $10,000 / 800 = $12.50.

Relative lift

Relative lift = Incremental conversions / Control conversions

Relative lift reflects the percentage conversion lift in conversions between the treatment and control arms. It’s computed as incremental conversions divided by the total control conversions. As a result, relative lift can theoretically scale between -1 and infinity. For example, if 90% of your conversions are incremental, you’ll have 90 incremental conversions for every 10 control conversions, resulting in a relative lift of 90 / 10 = 900%. Very large relative lifts can easily occur for brands with low control conversion activity in the control group.

Note: Relative conversion lift can be misinterpreted when comparing across different studies. For example, it will be much easier to get high relative lift for a study with a very low control as each incremental conversion will have a larger impact than a study with a very high control.

Conversion value metrics

Incremental conversion value

Incremental conversion value = treatment conversion value - control conversion value

The incremental conversion value reflects the treatment conversion value minus the control conversion value, in local currency, driven by your campaigns in the study period.

Note: Conversion value can vary widely. For example, someone purchasing a product or service for a company team event might purchase in bulk leading to a high conversion value when compared to typical everyday consumer behavior. This can make incremental conversion value more volatile than incremental conversions which can lead to larger confidence intervals for a Conversion Lift result.

Incremental Return On Ad Spend (Incremental ROAS)

Incremental return on ad spend = Incremental conversion value / Total ad spend

Incremental ROAS reflects the additional revenue generated for every dollar spent on advertising. It focuses on the revenue that would not have been earned without the campaign. For example, if your campaign generated $20,000 from a treatment group and $10,000 from a control group, your incremental revenue is $10,000. If your ad spend was $5,000, your incremental ROAS would be $10,000 / $5,000 = 2 or 200%.

What’s the difference between Incremental ROAS (iROAS) and ROAS?

iROAS: iROAS is calculated by subtracting the conversion value of the control group from the conversion value of the treatment group in the Conversion Lift study, and then dividing this number by the ad spend.

ROAS: ROAS is the overall measure of attributed conversion value divided by total spend.

Credible intervals and Confidence interval

These metrics reflect the estimated range in which your Conversion Lift result falls. Learn more about Conversion Lift study results.

Note: Google Ads uses modeling when a subset of conversions can’t be directly linked to ad interactions, typically due to browser restrictions and cross-device behavior. Make sure you're taking steps to capture conversions across devices so your conversion lift metrics accurately measure your campaign performance. To learn more about the impact on your specific study, reach out to your account manager.

Statuses

Learn more about how to interpret and use results of your Conversion Lift study.

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