What are key metrics indicating wasted spend on search campaigns?

Why search-spend leakage hides in plain sight

Google Ads exposes every metric needed to diagnose wasted search spend. The platform makes the reports hard to find on purpose. The default campaign view shows you cost, clicks, conversions, and a green optimization score that rewards more match types and more spend. The metrics that catch the leak sit two or three menus deep.

Pull six specific numbers across three reports. Cross-check them. Patterns appear fast.

Metric 1: search-term irrelevance rate

The report: search-terms inside Google Ads, last ninety days, sorted by cost descending.

Read the top two hundred queries and tag each one as relevant or irrelevant to your product. Divide irrelevant cost by total cost. That is your irrelevance rate.

A healthy search account on tight match types runs under ten percent. A Performance Max or broad-match heavy account often sits between thirty and sixty percent. Anything above twenty-five percent points at a structural mismatch between the keywords you are bidding on and the queries Google is matching you to.

The fix is rarely a longer negative-keyword list. The fix is tighter match types, audience signals layered on Performance Max, and a deliberate decision about where broad match operates.

Metric 2: Quality Score on top-spend keywords

The report: keywords view with the Quality Score column, Landing Page Experience, Ad Relevance, and Expected CTR columns added in. Sort by cost descending and look at the top thirty keywords.

A Quality Score below 5 on a keyword that takes more than a few percent of campaign spend is a tax. Google charges between fifteen and forty percent more per click on low-Quality-Score keywords than it charges competitors with strong scores. Multiply that across a six-figure account and the dollar figure is real.

Three Quality Scores below 5 in your top ten spend keywords is the threshold for a landing-page and ad-copy rebuild. Two together is a warning. One is noise.

Metric 3: impression share lost to budget versus impression share lost to rank

The report: campaigns view with Search Lost IS (budget) and Search Lost IS (rank) columns added.

These two numbers tell different stories. Lost-to-budget means the campaign is hitting daily cap and Google would spend more if you let it. Lost-to-rank means the campaign cannot win the auction at the bid and Quality Score it has, regardless of budget.

A campaign losing ten percent or more to budget while running a healthy conversion rate is leaving revenue on the table. A campaign losing thirty percent or more to rank on a low Quality Score is bleeding click cost on the impressions it does win. The two metrics dictate completely different fixes. Founders who only watch total spend never see either.

Metric 4: click-through rate on exact-match keywords

The report: keywords view filtered to match type equals exact, sorted by impressions descending.

Median ecommerce CTR on exact-match sits between 4 and 8 percent for branded queries and 2 and 4 percent for non-branded. A service business with strong intent queries should clear 5 percent on exact-match non-branded.

An exact-match keyword sitting under 1 percent CTR with meaningful impression volume is either matching to queries the keyword no longer represents, or showing an ad that does not address the search intent. Both situations cost you Quality Score, which compounds into Metric 2 and Metric 3 above. Pull the search terms for that single keyword and the diagnosis usually writes itself in five minutes.

Metric 5: conversion rate by match type

The report: dimensions or segment view, segmented by match type at the ad group level.

Exact match should convert at the highest rate. Phrase match a step lower. Broad match meaningfully lower than phrase. When the order inverts, when broad match converts higher than phrase, the data is lying. The reason is almost always a tracking de-duplication failure or a branded query slipping into broad match and inflating the read.

A broad-match conversion rate that doubles your exact-match rate on the same keyword root almost certainly means broad match is intercepting branded traffic that would have arrived through exact. You are paying Google to capture demand you already had. The Tracking Stack reference covers the de-duplication contract that catches this.

Metric 6: search-impression-share by audience segment

The report: audiences view inside a campaign, with impression share segmented by audience.

Customer Match lists fed from email and SMS should clock the highest impression share and the highest conversion rate inside any search campaign. Logged-in past purchasers searching for category terms are the cheapest conversions in the account.

If Customer Match audiences sit at low impression share while broad cold audiences absorb the bulk of campaign spend, the bid strategy is misallocated. Layer the audience as a bid modifier, raise the floor on Customer Match, and the same budget produces a different result inside two weeks.

The metric I look at first

The search-term irrelevance rate. It takes fifteen minutes to calculate and it tells you whether the account has a structural problem or a tuning problem. Everything else downstream, Quality Score, CTR, conversion rate, lost impression share, gets distorted by a high irrelevance rate. Fix the source and the other five metrics often correct themselves inside a month.

Run the free 25-page setup audit against the account if you want the full diagnostic written out, or read the rest of the wasted-ad-spend library for the adjacent leaks. A search account with two of these six metrics out of band is usually losing fifteen to thirty percent of its budget to friction the platform will never flag.

Founders who want me to walk the six-metric sweep against the live account instead of running it solo can book a thirty-minute call and send the account read-only.