positive-negativeAn effective keyword strategy is the cornerstone of any successful PPC campaign. When you’re paying for your advertising by the click, you want to make sure your ad is only being viewed by folks who are legitimately interested in what you’re offering. This means meticulously researching your keywords to capture the right traffic. It also means developing a robust list of negative keywords to filter out your unwanted results.

A negative keyword is one that will prevent your ad from appearing. For example, an optometrist who sells eyeglasses and sunglasses might choose “glasses” as one of his keywords. However, a term that broad will also crop up for people who are searching for drinking glasses, wine glasses, or shot glasses. To keep his ad from being served up to the wrong shoppers, he can add “drinking,” “wine,” and “shot” to his list of negative keywords.

Negative Keywords Mean Positive ROI

Negative keywords help you pinpoint the audience for your ad, which can be beneficial to your bottom line. Google determines your cost per click based on your ad’s quality score, which is derived in part from its click-through rate (CTR). So it follows that displaying your ad to relevant customers only will improve its CTR, which will improve its quality score and lower your cost per click. And a lower cost per click means a higher return on your investment.

Building a List of Negative Keywords

So how do you put together a list of keywords? Here are a couple of suggestions.

If your ad has already been running for a while, you can start by looking at your keyword report to see what search terms are causing your ad to display. Scan the list, looking for any terms that aren’t relevant to your business. For example, if your stationery business is generating impressions for “toilet paper,” then you’ll probably want to add “toilet” to your negative keywords.

There are also some preexisting negative keyword lists that you might find useful as a starting point. These may not be specific to your industry, but they’re definitely helpful for weeding out some of the more egregious searches (porn, sex, craigslist, ebay), as well as job seekers (career, hiring, jobs, salary), bargain hunters (cheap, discount, free, overstock), and researchers (guides, metrics, research, white papers).

Keeping Your Negative Keyword List Under Control

Technically speaking, there are no limits on how many negative keywords you can include in your PPC campaign. However, if your list becomes too unwieldy, you run the risk of sabotaging your own efforts. One misapplied negative keyword may prevent your ad from being served up to legitimate customers, but you’ll be hard pressed to find the culprit if you’re forced to scroll through hundreds (or thousands) of entries in a badly organized list.

A good rule of thumb is that your negative keyword list should never be larger than your primary keyword list. If it is, then you need to rethink your overall strategy for targeting keywords. When possible, you should try to eliminate negative keywords by converting them into multiple positive key phrases.

For example, let’s consider our optometrist from earlier in the article. It might be worthwhile to use the keyword “glasses” for his ad. However, if he discovers he’s getting more traffic from people searching for drinkware than eyewear, then he might want to forgo the keyword “glasses” and instead focus his marketing on “eyeglasses,” “eye glasses,” “sunglasses,” and “sun glasses.”


From time to time we republish some of our popular posts that are still relevant. This blog post originally appeared on January 10, 2014 under the title “Why You Need Negative Keywords.”