About similar keywords across ad groups

Your ads are eligible to appear when one of your keywords matches someone’s search term on Google or on search partner sites. But it may be that you have multiple keywords, from different ad groups, that match a given search term. For example, you might have identical keywords in two or more ad groups. Or you might have similar keywords – like plumber course in one ad group, and plumber training course in another – and both could match the search term training course for plumber. 

This article explains what happens when you have similar keywords that could match the same search term across different ad groups. You can also read more about what happens when you have similar keywords in the same ad group.

Note

Having multiple keywords that could match the same search term shouldn’t increase your costs in any way. The set of preferences detailed below determines which keyword is used to enter an ad into an auction. Once the ad enters the auction, it’s then compared with ads from other advertisers, and your cost-per-click is what's minimally required to hold your ad position and any ad formats shown with your ad, such as sitelinks.

How a keyword is selected 

If you have similar keywords that could match the same search term across different ad groups, the preferences below are used to determine which keyword is used to enter an ad into an auction. These are the same preferences used to select a keyword when you have similar keywords in the same ad group, but keep in mind that the process is more complex here. This is because different ad groups might have different ads, landing pages and campaign settings. All of these differences can result in varying experiences for customers, and can result in different Quality Scores for similar keywords in different ad groups. This will impact how the preferences are applied below.

The preferences rank approximately in the following order.

  1. A keyword that’s identical to the the search term

    If a keyword is identical to the search term, this keyword is preferred for triggering an ad, regardless of the ad group it’s in.

    Example

    Let's say that the search term is plumber course. If one of your ad groups includes the broad match keyword plumber course, while another ad group includes the phrase match keyword plumber, then the broad match keyword will be preferred because it’s identical to the search term.

  2. An exact match keyword when the keywords are identical

    If you have multiple ad groups with identical keywords, the exact match keyword is preferred for triggering an ad.

    Example

    Let's say that the search term is local plumber. If one of your ad groups includes the broad match keyword local plumber, and another ad group includes the exact match keyword local plumber, then the exact match keyword is preferred.

  3. The keyword that has the highest Ad Rank

    When several ad groups contain keywords that match a search term, the keyword with the highest Ad Rank is preferred for triggering an ad.

    Example

    Let's say someone searches for plumber training course and your ad groups include the keywords plumber course and plumber certification course.
    Keyword Ad Rank
    plumber course 1.5
    plumber certification course 1

    In this example, plumber course will be preferred because it has a higher Ad Rank.

    Note

    In rare cases, the keyword with the highest Ad Rank might seem to be less relevant to a particular search term than other eligible keywords. Because higher relevance is generally correlated with a higher Ad Rank, this should happen infrequently. Try running a search terms report to see instances in which the less relevant keyword triggers your ad. Then, add that search term as a negative keyword to the ad group that includes the less relevant keyword.

Exceptions to preferences

There are scenarios for which exceptions might be made and the preferences above might not apply.

A campaign is limited by budget

Your campaign's daily budget can affect whether the preferences above are applied. If a keyword is in a budget-restricted campaign, which means that the campaign's budget isn't high enough to accrue all possible traffic, the keyword won't always be able to trigger an ad even if it otherwise could. This helps prevent the campaign from greatly exceeding its budget. Learn more about how you can avoid a depleted daily budget.

Example

Let's say that your campaigns are called "Clogged Sinks" and "Broken Water Heater". In your "Clogged Sinks" campaign, you have the exact match keyword plumber, and in your "Broken Water Heater" campaign, you have the broad match keyword plumber.

All else being equal, the exact match keyword in your "Clogged Sinks" campaign would trigger an ad when someone searched for the term plumber because it's the more restrictive match type. However, if your "Clogged Sinks" campaign were budget-restricted, then the exact match keyword in this campaign would sometimes be unable to trigger an ad. This means that the broad match keyword in your "Broken Water Heater" campaign would trigger an ad instead.

There’s a cheaper keyword with a higher Quality Score and Ad Rank

On rare occasions, the preferences above might not apply if a keyword is cheaper – meaning it has a lower cost-per-click (CPC) bid – and has a higher Quality Score and a higher Ad Rank.

Example

Let's say that someone searches for plumber tool and you have the keywords plumber tools and plumber tool with the following maximum cost-per-click (max CPC) bid, Quality Score and Ad Rank:
 

Keyword Maximum CPC bid Quality Score Ad Rank
plumber tools £0.10 7 0.7
plumber tool £0.15 4 0.6

Usually, the keyword plumber tool would be preferred because it matches the search term more closely than the keyword plumber tools. However, the keyword plumber tools is cheaper and has a higher Quality Score and a higher Ad Rank. Therefore, the keyword plumber tools will be used in this scenario.

Note

In rare cases, the keyword with the highest Ad Rank might be less relevant to a particular search term than other eligible keywords. Because higher relevance is generally correlated with a higher Ad Rank, this will happen infrequently. Try running a search terms report to see instances in which the less relevant keyword triggers your ad. Then add that search term as a negative keyword to the ad group that includes the less relevant keyword.

There is an excessive number of matching keywords

If your account has hundreds of matching keywords, we’ll automatically remove some of the duplicates. Then we'll apply the preferences discussed above.

Example

Imagine that you copy an ad group 5,000 times, and so you now have 5,000 instances of the keyword plumber in your account. When a user searches for plumber, rather than process all 5,000 instances, we’ll reduce the number of matching keywords. Then, we'll use the preferences described above.

Tip

Use the Find Duplicate Keywords tool in Google Ads Editor to check whether you have multiple identical keywords in your account. Google Ads Editor is a free, downloadable application for managing your Google Ads account. 

One of your keywords has a low search volume status

There may be times when the preferences above don’t apply because a keyword has been given a low search volume status. This is a status given to a keyword that has very little to no search history on Google. Keywords with this status are temporarily inactive and won’t trigger ads. So, if you have a low search volume keyword, you’ll see a different keyword triggering an ad for a matching search term, even if according to the preferences above, your low-search volume keyword should have been the one to trigger the ad.

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