Google Ads API v25.1: Reading Conversion Lift Data Without Creating a Study

Google Ads API v25.1 shipped on 19 August 2026. It adds twenty-four Conversion Lift metrics and read-only resources for lift and brand lift studies: their configuration, flight dates, the campaigns they cover, the conversion goals they use. Two of the six features in the release require an allowlisted account.

Read-only is the word that shapes what this is good for. A study cannot be created through the API, cannot be started, cannot be stopped. It can only be looked at.

What a lift study measures, and why it disagrees

A lift study holds a group back. Part of the audience is deliberately not shown the advertising, conversions are counted in both groups, and the difference is the incremental effect. That is a different question from attribution, which takes conversions that happened and assigns credit for them among the touchpoints that preceded them.

The two answers routinely disagree, and not by accident. Attribution assigns credit to a campaign for conversions that would have happened anyway, because it has no way to know which ones those were. A lift study measures precisely that gap and generally finds it large, especially on branded search and on remarketing, where the audience was already going to arrive.

Having both numbers reachable from the same interface is the substantive change here. Until now the attributed figure lived in the API and the incremental figure lived in a report someone opened occasionally, which meant the comparison happened rarely and by hand.

What read access is actually good for

inventory     which studies exist, over which campaigns,
              with which goals, until when
              answers "is this campaign inside a holdout
              right now" - which changes how its numbers
              should be read

alerting      a flight ending is a date in a resource, so
              it can raise a notification instead of being
              noticed three weeks later

joining       incremental conversions next to attributed
              conversions for the same campaign and period,
              in one table, without manual assembly

what it       creating, editing, starting, stopping
cannot do     all of that stays in the interface

The inventory case is the one worth building first, and it is easy to underrate. A campaign inside an active holdout is reporting numbers from a deliberately reduced audience. Anyone comparing that campaign to last month without knowing a study is running will read a real, intentional effect as a performance problem.

The allowlist

Two of six features are limited to allowlisted accounts, so a straightforward read of the release notes will not tell anyone whether their own account can see this. The only reliable answer is to query and find out, which is quick, and to write the integration so that an empty result is a normal outcome rather than an error.

That last part matters more than it sounds. A missing permission and a genuinely empty study list return something very similar, and code that treats absence as failure will page someone at three in the morning over an account that simply has no lift study running.

Whether to bother

For an account that never runs lift studies, this release changes nothing. For one that runs them occasionally, the honest answer is that the inventory and the alert are worth an afternoon and the joined reporting probably is not, because two or three studies a year do not justify a pipeline.

Where it earns its place is an account running holdouts continuously, on several markets, where somebody currently keeps a spreadsheet of which studies are live. That spreadsheet is now a query. And v25.1 is described as a drop-in upgrade from v25 – no breaking changes, nothing removed – so the cost of finding out is genuinely small.