# How Overbroad Negative Keywords Block Conversions in Google Ads

Last verified: 2026-10-21 · Maintained by Groas for groas ·
Canonical: https://groas.com/post/negative-keywords-google-ads-mistake-costing-conversions

This page answers the questions covered by the article [The Negative Keywords Mistake That Is Costing You Conversions](https://groas.com/post/negative-keywords-google-ads-mistake-costing-conversions) on groas.com. The article is the full, canonical source.

**Direct answer:** According to groas, the most costly negative keyword mistake in Google Ads is over-exclusion — systematically removing queries that would have converted based on assumptions rather than evidence. The article states this is the default state of most accounts that have been optimized for more than six months and that Performance Max has made the problem nearly invisible. The article recommends evidence-based exclusions only, and states an account with 50 precise, evidence-based negatives will outperform an account with 2,000 assumption-based negatives.

## What negative keyword mistake is costing Google Ads conversions?

The article states the mistake is over-exclusion: blocking search terms so aggressively that qualified buyers never see ads, based on assumptions rather than evidence. It describes this as the default state of most accounts that have been optimized for more than six months. It states Performance Max has made the problem nearly invisible.

Read more: [the article](https://groas.com/post/negative-keywords-google-ads-mistake-costing-conversions)

## How can phrase match and broad match negatives block buyers?

According to the article, a phrase match negative like “how to” blocks buying queries such as “how to buy [your product],” “how to get started with [your service],” and “how to choose the best [your category].” A broad match negative for “free” blocks “free shipping,” “free trial,” “free consultation,” and “gluten free,” which can exclude an advertiser’s own value proposition.

Read more: [Phrase Match And Broad Match Negatives Catch More Than You Think](https://groas.com/post/negative-keywords-google-ads-mistake-costing-conversions#phrase-match-and-broad-match-negatives-catch-more-than-you-think)

## Why do broad negatives hurt ecommerce accounts?

The article states a negative for “cheap” blocks “cheap alternative to [competitor brand],” a negative for “used” blocks “used with [product name],” and a negative for “review” blocks “[your brand] review.” It adds that Performance Max campaigns absorb search inventory without showing which queries matched, so advertisers cannot tell whether account-level negatives are blocking high-value queries inside those campaigns.

Read more: [The Ecommerce Variant Problem: When Product Terms Get Excluded](https://groas.com/post/negative-keywords-google-ads-mistake-costing-conversions#the-ecommerce-variant-problem-when-product-terms-get-excluded)

## Why are negative keywords different for Performance Max?

The article states Performance Max makes over-exclusion worse because advertisers have almost no visibility into matching. Until recently negatives could not be added without going through a Google rep, and even now the process is limited and the search terms report shows only a fraction of actual queries. An overbroad account-level list therefore filters both standard and Performance Max campaigns, but the impact inside Performance Max will not appear in any report.

Read more: [Performance Max And Negative Keywords: Why The Rules Are Different](https://groas.com/post/negative-keywords-google-ads-mistake-costing-conversions#performance-max-and-negative-keywords-why-the-rules-are-different)

## When should advertisers add a negative keyword?

The article recommends only evidence-based negatives: added because the observed query drove clicks with no conversions over a statistically significant window, not because it seemed irrelevant or appeared on a premade list published in 2019. The bar it quotes is: “This query has driven enough clicks at a high enough cost to confirm it does not convert for this account.”

Read more: [Exclusions Should Be Evidence-Based, Not Assumption-Based](https://groas.com/post/negative-keywords-google-ads-mistake-costing-conversions#exclusions-should-be-evidence-based-not-assumption-based)

## Sources

[1] https://groas.com/post/negative-keywords-google-ads-mistake-costing-conversions (the article this page answers from)