Primary versus secondary conversions

In Google Ads, a primary conversion action can be used for bidding when the campaign optimises toward its associated goal. Secondary actions generally support observation in “All conversions.” Google's documentation also specifies a consequential exception: a secondary action included in a selected custom goal can be used for bidding.[1]

Inspect the campaign, not only the action

The label on an action is not the whole configuration. Review the campaign's selected goals, account-default goals and any custom goal. The question is whether that campaign is learning from the business outcome you intend.

Consider a hypothetical lead-generation account tracking a brochure download and an accepted sales enquiry. Both can be useful observations, but they express different levels of commitment. Combining them as equivalent successes can make the reported total difficult to interpret. Select an optimisation approach based on business relevance and available measurement, not on which event produces the largest number.

A compact audit

List each action, its trigger, source, counting unit and purpose. Identify duplicated representations of the same event across integrations. Check a known journey from website to CRM and review the campaign settings that use the event. Record your reasoning so the next person does not accidentally reverse it while tidying the account.

When changing optimisation signals, consider the maturity and reliability of the new outcome. A commercially meaningful but inconsistently recorded stage can still send misleading feedback. There is no universal setting that removes the need for a stable definition and a working implementation.

The takeaway: “primary” is part of an optimisation contract. It is not a quality badge awarded to every event that successfully fires. Review the contract whenever goals or integrations change.

Source

[1] Google Ads: conversion goals ↗, reviewed 26 October 2026.