In brief: A SEM audit is an ordered review of your Google Ads campaigns to detect where budget is leaking and what is holding back results. In this article I explain, from my experience with SMEs (small and medium-sized enterprises), what to review step by step: account structure, keywords and match types, search terms and negatives, ads and assets, bids, targeting, landing pages, and conversion tracking. I also show you how to interpret the key metrics (CTR, CPC, CPA, ROAS, and conversion rate) without getting lost in isolated numbers, and I include a checklist table so you can audit your own account today.
What a SEM audit is and when to carry one out
When I talk about a SEM audit I mean a systematic review of your paid search campaigns — normally in Google Ads — to understand what is happening inside the account and why you are getting the results you are getting. It is not a quick fix or an isolated trick: it is looking at the account from top to bottom with real criteria and comparing what is there with what should be there to meet your business objectives.
Before continuing, it is worth being clear on the difference between SEO and SEM, because each discipline is audited differently. In SEM we are working with a budget that is spent in real time, so every poorly made decision literally costs money every day that passes. That is the reason an audit has such value: what you fix today stops draining budget tomorrow.
When do I carry out an audit? I recommend considering it at several moments. When you inherit an account that was managed by someone else or by an agency and you do not know how it is set up. When you have been spending for weeks without seeing clear conversions. When the cost per acquisition rises without an obvious reason. Before increasing budget, because there is no point putting more money into a structure that does not convert. And as a minimum, once a quarter as preventive maintenance, even if everything seems to be working.
What to review step by step in a SEM audit
Here is the walkthrough I follow, in the order that makes sense. The idea is to go from the general (how the account is organised) to the specific (which keyword is burning money), because structural problems contaminate everything below them.
1. Account structure and campaigns
The first thing I look at is whether the account has a clear logic. I review how campaigns are separated (by product or service type, by objective, by geographic area) and whether ad groups are specific enough. An ad group that mixes dozens of keywords from different themes almost never works, because it is impossible to write an ad that is relevant to all of them. I also check that campaign types (Search, Display, Shopping, Performance Max, Video) are properly differentiated and not overlapping by bidding against each other for the same queries.
2. Keywords and match types
Here I review which keywords are active and, crucially, which match type they are set to. Google Ads offers broad match, phrase match, and exact match, and each opens the door to a very different volume of searches. Broad match can bring a lot of traffic, but also a lot of noise if you do not control it with negatives. I check that the match type choice makes sense for each keyword and that there are no generic terms on broad match consuming budget without purchase intent behind them.
3. Search terms and negative keywords
This is one of the areas where the most money is recovered. One thing are the keywords you are bidding on, and another entirely are the actual search terms users typed that triggered your ads. In the search terms report there are almost always queries that have nothing to do with what you sell. I go through that report in depth and add as negatives everything that does not fit, and I check that well-maintained negative keyword lists exist. Without negatives, the account bleeds budget on irrelevant searches.
4. Ads, extensions, and assets
I review ad copy to see if it is relevant to the keywords in the group, whether it communicates a clear value proposition, and whether it includes a call to action. I check that there are several ads per group so the system can compare and optimise. I also look at assets (formerly called extensions): sitelinks, callouts, structured snippets, call, location. Good assets increase ad visibility and typically improve performance at no extra cost, so their absence is a very common missed opportunity.
5. Bids and budget
Here I analyse the active bidding strategy (manual, maximise conversions, target CPA, target ROAS) and whether it is coherent with the campaign objective and the data available. Automated strategies need a reasonable volume of conversions to work well; applying them in an account that barely converts usually produces erratic results. I also review how budget is distributed: if the best-performing campaigns are limited by lack of budget while others that do not convert are consuming it, there is a clear redistribution to make.
6. Targeting
I check geographic, time-of-day, device, and audience targeting. It is very common to find campaigns showing in areas where the business does not operate, or at times when no one is available to respond. I check whether bids are the same on mobile as on desktop when the data shows one converts much better than the other, and whether audiences and exclusions are properly defined to avoid spending on profiles that will never buy.
7. Landing pages
A flawless ad is worthless if it leads to a slow, confusing page that does not match what the ad promised. I check that each ad points to the most relevant page — not the homepage by default — that the page loads quickly, looks good on mobile, and has a visible call to action. The coherence between keyword, ad, and landing page is decisive both for converting and for Quality Score.
8. Conversion tracking
For me this is the most important point in the whole audit, because without correct measurement all other decisions are made in the dark. I verify that conversion tracking is properly configured, that it records the actions that genuinely matter to the business (a form submission, a call, a purchase) and not intermediate clicks that mean nothing. I check for duplicate conversions, that values are correctly assigned where relevant, and that conversion imports are working if used. An account that measures poorly looks like it works or like it does not work — when in reality nobody knows.
9. Quality Score
Quality Score is Google's assessment of the relevance of your keywords, your ads, and your landing page. I review its three components: ad relevance, expected click-through rate, and landing page experience. A low Quality Score typically indicates that something in that chain is broken, and improving it not only helps you appear better positioned but also tends to reduce what you pay per click.
SEM audit checklist
| Area | What to review | Warning signal |
|---|---|---|
| Structure | Campaigns and groups segmented clearly by objective or theme | Groups with mixed-theme keywords |
| Keywords | Match types consistent with intent | Generic terms on broad match without control |
| Search terms | Report reviewed and negatives applied | Irrelevant queries triggering ads |
| Ads and assets | Multiple ads per group and active assets | Single ad and no sitelinks |
| Bids and budget | Strategy aligned with objective and efficient distribution | High-performing campaigns budget-limited |
| Targeting | Correct area, schedule, device, and audience | Ads showing outside operating area |
| Landing pages | Relevance, speed, and mobile version | Everything pointing to the homepage |
| Conversions | Tracking configured and no duplicates | Measuring clicks instead of value actions |
| Quality Score | Relevance, expected CTR, and page experience | Consistently low score across the account |
Key metrics and how to interpret them
Once the structure is reviewed, it is time to read the numbers. Here is how I interpret the main metrics, because no data means anything in isolation — it always has to be looked at in context and in relation to your objectives.
CTR (click-through rate) tells me what proportion of people who saw the ad clicked on it. A low CTR usually points to ads that are not very relevant or to keywords that do not match what the user is searching for. CPC (cost per click) is what you pay on average for each click; I analyse it alongside Quality Score and competition, because a high CPC can be due to a highly contested sector or to improvable relevance.
CPA (cost per acquisition) is what it costs you to obtain one conversion — and this is where things get really important: a cheap click is worthless if it never converts. ROAS (return on ad spend) relates the revenue generated to the investment, and it is the metric that best connects the campaign to business profitability. And conversion rate tells me what percentage of clicks end in the action you are looking for; when it is low, the problem usually lies in the landing page or in the tracking rather than in the ad.
I am not going to give you specific benchmark figures because they would be misleading: what is reasonable varies enormously by sector, competition, and product type. What is useful is to compare your metrics against your own historical data and your objectives, and to understand the relationship between them. If you are wondering about order-of-magnitude investment, it will help to read about how much a SEM campaign costs for an SME.
Common mistakes that drain budget
After reviewing many accounts, the same errors come up over and over. The first and most serious is not measuring conversions correctly or not measuring them at all: without that, everything else is guesswork. The second is the absence of negative keywords, which leaves the door open to irrelevant searches consuming budget day after day.
Another classic is sending all traffic to the homepage rather than to a specific page that responds to what the user was searching for. I also frequently see ad groups overloaded with unrelated keywords, automated bidding strategies activated without enough data for them to work, and campaigns that nobody has touched for months. Inertia is expensive: what worked six months ago may be burning money today.
Finally, a costly strategic mistake is treating SEM in isolation from the rest of the strategy. A good SEO audit and a SEM review complement each other, because both look at the same user experience from different angles. Looking only at the campaign without looking at the website it leads to is doing half the job.
Conclusion
A well-done SEM audit is not a luxury — it is the fastest way to stop losing money and to put every euro to work. Review the structure, control match types and negatives, take care of ads and landing pages, make sure you measure conversions correctly, and read the metrics in context. With that routine, your account stops being a black box and becomes a tool you can continuously improve.
If you would prefer to have someone with experience go through it, in my SEO and SEM consultancy I follow exactly this walkthrough on SME accounts. Tell me about your case and we will look at it together: an audit at the right time usually saves far more than it costs.