Why is broad match a bad idea in Google Ads?

Your keywords are the words you tell Google you want to advertise on. Search terms are what people actually type. A match type decides how closely a search has to match your keyword before your ad can show.

There are three match types. Exact match is the strictest: your ad shows for searches that mean the same thing as your keyword. Phrase match is looser. Broad match is the loosest, and it's what you get if you type a keyword in with no symbols around it.

With broad match, Google can show your ad for searches that are only loosely related to your keyword, based on its own judgement of what's relevant.

You pay for every click, relevant or not, and Google earns money from every one. That's worth keeping in mind when it describes a search as relevant to you.

Here's an example. A resin driveway installer used the keyword "resin driveways" on broad match. Their ads were shown for searches like:

• "disadvantages of resin driveways": someone looking for reasons not to buy one
• "diy resin driveway": someone who wants to do it themselves
• "how to lay a resin driveway": someone looking for a tutorial

All of those are related to resin driveways. None of them is a customer. The business paid for every click.

This wouldn't matter if clicks were free. They aren't, and these clicks rarely convert well enough to pay for themselves. In dozens of analyses we've run, the cost per acquisition on broad match keywords has consistently been at least double that of exact match.

The damage often goes unnoticed because nobody reads the search terms report, which shows what people actually typed before clicking.

Google's position is that broad match works well with smart bidding, where Google sets your bids automatically, and with plenty of conversion data to learn from. It can also find searches you'd never have thought of.

That's Google's claim, and it isn't what our own analyses show. It may hold for large accounts with lots of conversions and someone checking the search terms regularly. A small account usually has neither. With little data, Google has less to learn from, so more of your budget goes on testing out searches that don't convert.

If you haven't used broad match, don't start. Use exact match keywords that nearly everyone typing them would want what you sell. Exact match isn't completely literal, because Google still shows your ad for close variations with the same meaning, but it's far tighter.

If you already use broad match, go to your search terms report and find the searches that actually produced enquiries. Add those as exact match keywords. That's your foundation. Then add the irrelevant searches as negative keywords, which stop your ad showing for them.

Broad match hands Google control of who sees your ad, and you pay for the result. Use exact match, read your search terms, and add what works.