Google Ads Optimization: A Practical Audit for Rising Costs and Falling Conversions

Google Ads Optimization: A Practical Audit for Rising Costs and Falling Conversions

Your Google Paid Ads channel over the last few months has started to underperform, and the dashboard is the last place to admit it. Cost-per-click has climbed, and the same monthly budget produces fewer conversions. 

You have been diligent in monitoring for cannibalization between Paid and SEO; you have kept up to date on your keywords and negative keywords list, and there have been no major changes to your Ads account. Yet, your Return on Ad Spend (ROAS) and Gross Return on Investment (ROI) from the channel you report on are falling short of the expected targets. If you haven't launched Google Ads yet, our guide to how much Google Ads costs in Canada is the better place to start; this piece is for accounts already running where the returns have quietly slipped.

Rising costs and falling conversions rarely trace back to one clean cause. 

They usually stack: 

• A shift in the auction you're bidding into
• A Quality Score that's been decaying quietly for months
• A landing page that no longer matches the ad pointing to it
• A conversion action Google has been optimizing toward that never mapped to a real customer
• An ad variant that's stopped connecting and is still running
• Or an account structure still built around outdated ad group logic

These are the common culprits we find when auditing a Google Ads account. Before we go into depth on these topics, we first want to address the elephant in the room around campaign optimization scores and industry benchmarks. These signals are recalculated fresh for every auction. If you are looking to understand better how to improve these scores check out our article on Google ads optimization. We cover in depth on common root causes we see for rising costs and falling conversion.

Your Campaign Optimization Score and Conversion Rate Benchmarks: A Warning Before Chasing Metrics over Results

Your campaign optimization score looks like a health check, a percentage next to a list of Google's recommendations, shown at the campaign level and rolled up across your account, with the implication that reaching 100% means things are fine.

It isn't a health check. 

The score measures how closely your campaigns match Google's own recommended settings, broader match types, automated bidding, and more ad extensions. 

It's tempting to chase a perfect score, and the 100% framing is built to make you want to. 

Instead, take a minute to pull up your own account's recommendations list, and you'll usually find the top items are things like turning on AI Max or adding broad match keywords, changes that expand reach and spend more than they improve your results.

Treat the recommendations list with scrutiny, especially anything that suggests changing your bid strategy. 

Many of these recommendations lead to settings that spend more, whether or not they improve your results. That doesn't automatically mean they help your results too, so weigh each one against your own account history before applying it.

A second issue we see customers striving for is hitting industry conversion rate benchmarks.

They vary enormously within an industry. 

Yes, while most companies are looking to average benchmarks to determine if their campaigns are doing well, what most benchmark reports don't disclose is the offer type, the data's geography, the quality of the underlying data, sample size, or what else was running alongside paid.

Many of the guides publishing these benchmarks are written by vendors with a service to sell. Worth checking who published the number and why before you treat it as a target.

Before you go looking for outside help, we have put together an audit checklist to help you find the root cause of your falling conversion rates and rising costs. This is an abridged version of the process our Digital Marketing services team uses when analyzing new accounts and tracking down a drop in channel effectiveness.

Google Ads Audit: The 6 Most Common Causes of Rising Costs and Falling Conversions

Here is an overview of each of the six causes we listed earlier, and what to do to uncover the root cause and fix it.

Auction Shift

A shift in the auction is the easiest to miss because nothing in your account changed. This change happens over time, and you finally realize it a month or a quarter down the road when your metrics are falling short. Here is what to do.

Pull the Auction Insights report (Left tab menu: Campaigns>Insights and reports>Auction Insights) on your core ad groups (filter at the top) and look for new entrants or a shift in overlap rate or position above rate among competitors you already track. If you aren’t tracking, use the time filter to compare previous time periods. 

• Overlap rate is the closest thing to a direct fingerprint of a new or more aggressive competitor. It measures how often a specific domain showed up in the same auction as you, at the same time you showed up. A domain with 0% overlap becoming 10%+ over a few months is literally the auction shifting under you.
  
  • What to do: If a domain's overlap rate has climbed meaningfully over a comparable period, don't react by raising bids across the board. Check what changed on their end first: new offer, new ad copy, or a seasonal push. You can check most of this through Google's Ads Transparency Center or by visiting their site for new offers. What matters is whether to compete harder on the specific keywords where you're overlapping or accept the share loss and focus budget elsewhere.
    
    
• Position above rate answers the follow-up question overlap rate can't: when that competitor shows up with you, are they beating you? A position above rate that keeps climbing over a comparable period means they're now winning the position fight more often. Look for that sustained trend across several periods rather than acting on any single reading.
  
  • What to do: A high position above rate against a specific competitor usually points to Ad Rank. That's Quality Score and landing page territory, covered in the next two points.

Quality Score Decay

Pull the Quality Score column at the keyword level for your core terms and check the trend, not just the current number. 

Quality Score breaks into three components: expected click-through rate, ad relevance, and landing page experience, and a drop in any one of them raises your cost per click and can cost you position at the same time. 

The problem is Google mostly gives you a score. Hovering over each status column for each keyword will sometimes surface a specific reason, but not consistently enough to rely on. Add the following columns: Quality Score, Landing page experience, Expected CTR and Ad relevance, along with their historicals.

Across the three components below, compare your historical columns to their present ones. If you see a drop, work through the what-to-dos.

• Ad relevance: how closely your ad matches the intent behind the keyword. Below average usually means the keyword no longer belongs in that ad group.
  
  • What to do: Move the keyword into a tighter, more specific ad group. For example, split "home insurance," "business insurance," and "renters insurance" into their own ad groups instead of running them together under one generic insurance group.
    
    
• Expected click-through rate: how likely your ad is to get clicked for that keyword compared to competitors targeting it. Below average here usually means the ad copy itself isn't compelling enough for the keyword's intent.
  
  • What to do: Rewrite the ad copy to speak directly to that keyword and test it against your current version. This includes headlines and descriptions. What matters most right after you've restructured ad groups is aligning the changes like "Lowest Homeowner Insurance" with a page centred around homeowner insurance.
    
    
• Landing page experience: how relevant and useful your landing page is to someone who clicked from that keyword's ad. Think of this as the match between what they read in the ad and the experience your page serves.
  
  • What to do: covered in the next point.

Landing Page Mismatch

Pull your top landing pages by spend (Campaigns > Ads & assets > Landing pages) and check each one against the ad copy currently pointing to it. Pages get redesigned, rebranded, or replaced for reasons that have nothing to do with paid media, and the ad copy pointing to them rarely gets updated in the same motion.

• Destination check: confirm the final URL still resolves to a live, correct page rather than a redirect, a 404, or a page that's been replaced since the ad was built. While this seems obvious, things can be changed without you knowing, especially in businesses where multiple people have access.
  
  • What to do: Update the final URL to the correct current page, or pause the ad until it's fixed.
    
    
• Message match: confirm the landing page's headline and offer still say what the ad promises. A landing page that's drifted from the original offer also degrades how well Google's own matching works, since the page content itself is one of the signals broad match uses to judge intent.
  
  • What to do: Rewrite the landing page or the ad copy so the two match again, whichever is cheaper to fix. Ensure your main keyword is hitting the H1 tag. 

One thing to watch for with landing page mismatch: it often ties directly into ad group restructuring. If you've split one general ad group into several more focused ones, each new ad group needs its own landing page built around that specific keyword theme. Your offerings can stay the same; the copy still needs to change.

For example, splitting a general "engineering services" ad group into "mechanical engineering services" and "electrical engineering services" means each new ad group needs its own focused landing page. 

Without creating new pages, you'll end up with the same misalignment problem the Quality Score and audit sections above are built to catch, just self-inflicted this time. This same ad group split shows up again in the account structure point later in this audit, worth reading both together since one covers the page side and the other covers the bidding side.

Conversion misconfiguration

Pull the conversion actions report and check what Smart Bidding is actually optimizing toward.

• Wrong conversion: the conversion action itself was never the right target. A tracking pixel can also break silently after a website update, a consent banner change, or a CMS migration, with no error thrown, so the dashboard keeps reporting numbers that no longer reflect reality. If Smart Bidding has spent months optimizing toward form submissions instead of qualified leads, it will get very good at generating the wrong thing.
  
  • What to do: Check the Goals and Conversions page (Goals > Conversions > Summary) for exactly which action is set to Primary, and confirm it maps to a paying or qualified customer. One step further: depending on your CRM, you can import closed-won data from actual purchasing customers to give Smart Bidding a stronger signal to train on.
    
    
• Too many primary conversions: marking multiple actions Primary at once (form fills, calls, newsletter signups, page views) blends them into one optimization target with equal weight by default. Smart Bidding chases whichever is easiest to generate, and setting up conversion this way leads to trouble later on.
  
  • What to do: Move low-intent actions to Secondary so they're still tracked but no longer driving bids, and assign conversion values to Primary actions so Smart Bidding can tell the difference; a demo booking might be worth $100 or more, while a brochure download is closer to $1.

Underperforming Ad Variants

• Asset Level performance: pull the asset-level performance report for your core ad groups (Ads & assets, open a Responsive Search Ad to see each headline and description rated Low, Good, or Best). An asset stuck at Low performance for several months straight is the ad copy equivalent of fatigue; it's not connecting, and Google's already told you which specific pieces.
  
  • What to do: Pause or replace any asset rated Low performance for an extended stretch, and write new headline and description variants to replace them. Give Google's asset rotation enough time to generate a new performance read before judging the swap

Traditional Ad Group Setup

Account structure problems compound all of this. Historically, search was centred around Single Keyword Ad Groups (SKAGs), one keyword per ad group across every match type was standard advice through 2015 to 2018, built on the idea that hyper-specific ad copy maximizes Quality Score.

A common reason ad groups are still stuck as SKAGs is that marketers rebuild what worked before because keeping up with every algorithm shift is a full-time job on its own.

Since Google expanded close variants and shifted toward Smart Bidding, the SKAG structure increasingly starves the algorithm of the data it needs: too few searches per ad group to learn from. 

Most accounts now perform better with Single Theme Ad Groups (STAGs), 5 to 15 closely related keywords across 7 to 10 ad groups per campaign, giving Smart Bidding enough volume while keeping ad copy focused. One documented SKAG consolidation saw cost-per-opportunity improve 6% in the first month and 27% in the second, with no drop in volume. 

SKAGs still earn their keep in narrow cases, brand protection terms, high-margin services, or campaigns where you need to know exactly which query triggered a click. These are rare and generally managed by a person who understands the pros and cons and, more importantly, when to call it quits if this isn’t working.

When to Fix It Yourself vs When You Need a Managed Account

A single, identifiable problem, like one broken tracking tag, one outdated landing page, one bid strategy mismatched to a recent drop in conversion volume, is usually something an in-house team can fix once the audit framework above surfaces it. 

The harder cases are the ones where several small issues have accumulated at once: Quality Score has drifted, the audience signal has been wrong for months, and the account structure has grown messy through a year of ad hoc changes. Another common trigger is a change of hands: in-house staff leave, contractors move on, and the nuances of what they were doing get lost in the handoff. Untangling that combination takes more time than most in-house teams have room for, and leaving it half-fixed just means more budget spent chasing a partial recovery.

AI can help untangle the mess, but only if the person asking the questions knows when to push back or when an answer is wrong. Following AI's advice blindly can create bigger problems that take longer to fix.

If your account has been declining for more than a quarter and the cause isn't obvious after a first pass through the framework above, that's the signal it's time for a full audit from our paid media management team.

Ready for a Clear Answer?

If your Google Ads account has been costing more and converting less without an obvious explanation, we offer a free review of the account. Book a consult with our Digital marketing Team. 

Frequently Asked Questions

Why are my Google Ads costs going up while conversions are dropping?

The two usually share a root cause: a drop in Quality Score, which raises your cost per click and can cost you position in the auction. Common triggers include a new competitor in the auction, a landing page that no longer matches your ad copy, broken conversion tracking, or an automated bid strategy optimizing toward the wrong signal. A structured audit of your search terms, Quality Score, and tracking setup will usually identify which one is happening in your account.

How do I optimize my Google Ads account?

Start with an audit rather than a list of tactics: review your search terms report for irrelevant traffic, check Quality Score on your core keywords, confirm your landing pages still match your ad copy, and verify your conversion tracking reflects real customers rather than low-intent form fills. Fix what the audit actually finds instead of applying generic best practices that may not apply to your account.

What is Google's Ads optimization score, and should I follow it?

It's a percentage that measures how closely your account matches Google's own recommended settings, not a measure of how well your account is actually performing. Following every recommendation can raise your score while raising your cost-per-conversion, since many recommendations push toward broader targeting and automated settings that favour Google's platform over your specific results. Evaluate each recommendation individually against your own account history rather than chasing a higher score.

How often should I audit a Google Ads account?

A full audit once a quarter is a reasonable baseline for most active accounts, with a lighter check of search terms and Quality Score monthly. Any account showing a sudden shift, cost climbing, conversions dropping, or both, should be audited immediately rather than waiting for the next scheduled review.

What is a good conversion rate for Google Ads?

There isn't a single number that applies across industries, offer types, and funnel stages. Any figure should be treated as a fuzzy reference point, not a target. What matters more is the trend in your own account: a rate that's fallen significantly over recent months signals a real problem worth auditing, even if it's still near an industry average.

Are Single Keyword Ad Groups (SKAGs) still a best practice in Google Ads?

Not as a default, though it's a genuinely contested question among experienced PPC practitioners, not a settled fact. A SKAG is literally one keyword per ad group across every match type, not a keyword clustered with synonyms. Since Google expanded close variants and match types loosened, most accounts now perform better with Single Theme Ad Groups (STAGs), roughly 5 to 15 closely related keywords across 7 to 10 ad groups per campaign, because that gives Smart Bidding enough data density to optimize. SKAGs still have real defenders for high-value, low-volume keywords where precise control matters more than data density.

References

Schiele, L. (2025, November 12). How to consolidate legacy SKAGs – and why it's time to move on. Search Engine Land. https://searchengineland.com/consolidate-legacy-skags-464518

Google. (n.d.). Ads Transparency Center. Retrieved September 21, 2026, from https://adstransparency.google.com/