Impression Share vs. Conversion Share: Which Google Ads Metric Actually Predicts Revenue for Local Businesses

The Metric That Looks Like a Win (But Often Isn't)

Your Google Ads dashboard shows 78% impression share. Your rep says that's strong. You feel good about it.

Then a competitor with 45% impression share wins more jobs than you do this month.

That's not a coincidence — it's a measurement problem. Impression share (IS) tells you how often your ad showed up. Conversion share tells you how often your ad drove action. Running a local service business on IS alone is like judging a restaurant by how many people walk past the window instead of how many actually eat there.

This post tears down why the gap between the two metrics is where overspend hides — and gives you a concrete model to find it in your own account.

What Each Metric Actually Measures

Impression Share = (Your impressions) ÷ (Total impressions your ads were eligible for). It reflects reach and auction competitiveness — how much of the potential audience saw you.

Conversion Share is a less-standard column that, when constructed from available data, reflects what proportion of total tracked conversions your account is capturing relative to the competitive landscape. In practical terms, most local advertisers approximate it by tracking their own: conversion rate × click share × quality score efficiency.

The key distinction:

• IS is an input signal — it tells you about your bid posture and budget ceiling.
• Conversion rate, cost-per-conversion, and revenue-per-conversion are output signals — they tell you what that spend actually produced.

Google's own guidance separates these clearly: impression share is a coverage metric, not a performance metric. Treating it as a proxy for performance is where most local accounts go wrong.

The Gap Analysis: A Modeled Example

Here's a labeled illustrative model built around typical numbers we see in local service accounts. These are not cited benchmarks — they are worked examples to show the math.

Account A — High IS, Low Conversion Efficiency

• Impression Share: 80%
• Click-Through Rate: 4%
• Conversion Rate: 3%
• Illustrative monthly spend: $4,000
• Estimated conversions: ~48
• Estimated cost-per-acquisition (CPA): ~$83

Account B — Moderate IS, High Conversion Efficiency

• Impression Share: 45%
• Click-Through Rate: 7%
• Conversion Rate: 9%
• Illustrative monthly spend: $4,000
• Estimated conversions: ~113
• Estimated cost-per-acquisition (CPA): ~$35

Same budget. Account B generates roughly 2.3× more conversions at less than half the CPA — not because it dominated the auction, but because its targeting, ad relevance, and landing page converted the clicks it did get.

The takeaway: Account A is paying a premium to show up everywhere. Account B is paying to close. If you're managing budget like Account A, you're likely funding your competitors' margins.

Why Local Accounts Get Trapped in High-IS, High-CPA Mode

Three patterns drive this trap:

1. Broad match + max clicks bidding. This combination chases impression volume efficiently — Google is literally optimized to get you more impressions. Without a conversion target, it has no reason to filter for intent.

2. Weak landing page alignment. Even with great ad copy, if the page doesn't match the query's implied promise, visitors bounce. IS stays high; conversions don't follow. (If you've read our breakdown of Smart Bidding: How Many Conversions Do You Actually Need?, you'll recognize this as the data-starvation problem — Smart Bidding can't optimize toward conversions it never sees.)

3. Wrong campaign objective. A campaign set to 'Awareness' or 'Reach' will happily maximize IS at the expense of conversion volume. This mirrors the cost pattern we covered in Wrong Meta Objective? Here's What It Costs You — the same principle applies to Google.

The structural problem: Google's interface surfaces IS prominently. It's easy to pull, easy to screenshot for a client report, and it feels intuitive. Conversion share requires you to actually build the measurement infrastructure — conversion tracking, attribution, ROAS columns — which many local accounts skip.

The Benchmark Reality Check

One genuinely well-established industry reference point: WordStream's Google Ads benchmarks for local services categories consistently show average conversion rates in the 2–5% range for broad local service verticals (home services, legal, health), with top-quartile accounts converting at 10–12%.

That gap — 3% vs. 11% conversion rate at the same CPA bid — mathematically produces a 3–4× difference in cost per acquisition for identical spend levels. This is the IS trap in numeric form: an account running at 3% CVR with 80% IS is structurally more expensive than an account at 11% CVR with 50% IS, even if the lower-IS account looks 'weaker' on the dashboard.

(Note: We're citing the directional range from WordStream's benchmark reports as a widely-known industry reference. Verify the current-year figures at wordstream.com/google-adwords-industry-benchmarks before building internal targets.)

The Audit Framework: Four Columns to Pull Right Now

Open your Google Ads account and add these four columns to your campaign view. Compare them side by side:

1. Impression Share — your coverage metric 2. Click Share — how much of available clicks you're capturing 3. Conversion Rate — the efficiency of what you captured 4. Cost / Conv. — the actual acquisition cost output

The signal pattern to look for:

| Pattern | What It Means | |---|---| | High IS + Low Conv. Rate | Reaching the wrong audience, or landing page is leaking | | Low IS + High Conv. Rate | Budget is capping a machine that's actually working — scale it | | High IS + High Conv. Rate | Competitive and efficient — defend this with smart bidding | | Low IS + Low Conv. Rate | Signal problem — check tracking before anything else |

The worst position for a local business is top-left: paying for dominance in an auction where your creative and page can't convert. Raising bids to hold IS in that state compounds the problem.

If you're in the bottom-right quadrant, fix measurement first — as we've covered in One Channel Deep vs. Many Channels Thin: ROAS Reality, scaling spend without clean conversion data just amplifies noise.

What to Optimize Instead

Once you've run the four-column audit, here's the priority order:

1. Confirm conversion tracking is firing correctly. A misconfigured tag is the single most common reason conversion share looks artificially low while IS looks fine.

2. Segment IS Lost (Budget) vs. IS Lost (Rank). Google breaks down why you're losing impressions. Lost to budget = your ceiling is too low on something working. Lost to rank = quality score or bid relevance issue. These require opposite fixes.

3. Set a CPA or ROAS target before chasing IS. Smart Bidding needs a goal signal. Without one, it defaults to volume — which is IS maximization by another name.

4. Audit landing page conversion rate independently. Use a tool like Google Analytics 4 or Microsoft Clarity to watch session behavior on your landing page. A page converting at 2% with improvements to 6% triples your effective conversion share without touching your bids.

The mental shift: Stop asking 'How much of the market am I reaching?' Start asking 'Of the market I reach, how much becomes revenue?' That's the question that predicts profit.

The Bottom Line

Impression share is a useful diagnostic — it tells you whether your budget and bids are competitive enough to participate in the auction. It is not a revenue predictor. Conversion share, cost-per-acquisition, and ultimately ROAS are the metrics that connect ad spend to business outcomes.

Local businesses running on IS as their north star metric typically find, when they do the gap analysis, that they're overpaying per acquisition by a significant margin — not because their market is too competitive, but because they've been optimizing for the wrong signal.

If you'd like to run this audit on your actual account — and see where your IS-to-conversion gap is creating margin leakage — book a free strategy call with the Nika Spark team. We'll pull the four columns, map your quadrant, and show you exactly which lever to move first.