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Broad Match Modifiers: A Big Difference Between Bing and AdWords You May Not be Aware Of

Broad Match Modifier (BMM) is a match type available in Google AdWords, Bing Ads and Yahoo Gemini which allows advertisers to place plus signs in front of words within a keyword in order to tell the engines that those words should be present in order to be included in auctions the keyword might broad match into.

For example, advertisers launching the BMM keyword ‘+green +Nike shoes’ have the intention of that keyword only being featured in auctions that contain both the terms ‘green’ and ‘Nike.’ Shoes would not be a necessary term and the keyword could broad match into auctions for queries that don’t mention ‘shoes.’

Close variant matching throws a wrinkle into this match type with Bing and Google, as both engines allow close variants of the terms with pluses in front of them to trigger BMM keywords. In the example above, ‘Nikes’ would be deemed sufficiently close to ‘Nike’ to qualify the BMM keyword for the query ‘green Nikes shoes.’

Note: Gemini’s literature on BMM simply states that the modified term ‘must be part of the user query,’ with no mention of close variants.

Close variants are defined by Google as ‘misspellings, singular forms, plural forms, acronyms, stemmings (such as floor and flooring), abbreviations, and accents’ and by Bing Ads as ‘minor grammatical variations, such as plurals, abbreviations, acronyms, spacing and misspellings.’

Thus, throwing a plus sign in front of a term within a keyword doesn’t guarantee that that exact term will be in the query someone is searching for on either search engine, but close variants are still meant to be very close variations of the modified term.

However, advertisers might be surprised to learn that while Google explicitly states that synonyms will not be considered for modified terms, Bing Ads allows for ‘equivalent expressions.’ Whereas close variants are meant to be limited to variations of a specific term, equivalent expressions are meant to include totally different ways of expressing the same idea, with or without reference to the specified term.

This opens up a whole host of matching options for BMM keywords in Bing Ads which are not a possibility with AdWords BMM, and calls into question whether Bing’s version of the match type is really accomplishing what advertisers are attempting to get at when they add BMM keywords.

‘Equivalent Expressions’ Appear to Cast a Very…Broad Net

According to Bing’s own example from their help page on the subject, ‘equivalent expression’ appears to essentially mean ‘synonym,’ as the term ‘cabin’ can qualify for the modified term ‘lodge’:

That’s kind of a big deal, as you might think the whole point of BMM is to ensure that a specific term is used in the query being searched for in order for a keyword to be eligible for the auction.

However, what Bing’s system deems a synonym is in some cases much worse than a simple ‘cabin’ for ‘lodge’ switcheroo, as several Merkle analysts have found in analyzing search query reports.

For example, the query ‘winter coats for discount’ matched to the BMM term ‘+{redacted brand name} +big +and +tall +clothing.’ There’s not a whole lot of commonality between that query and the keyword, and the fact that there are broad match modifiers on every single term in the keyword makes this match even more egregious.

Of course, advertisers can use negatives to prevent specific queries from triggering BMM keywords based on query reports, and you should be checking these reports regularly for your BMM campaigns to ensure your keywords are matching queries in the way you intend them to.


Unfortunately for advertisers, the current state of BMM on Bing Ads isn’t such that you can simply copy over your BMM campaigns from AdWords and assume the query matching will be similar. As such, it’s important to stay vigilant of query reports for these campaigns, and actively work to ensure that they are matching to the right queries.

Hat tip to Jessica Vermaat, Kirstin Ladas, Alex Ross, and Kelly McGee for getting to the bottom of Bing BMM.