Keyword Match Types
Broad Match (very little control)
Shows your ads if a search query contains your keywords in any order, and along with other terms. Your ads will also appear for singular and plural forms, synonyms, stemmings etc. So for example, if your broad match keyword is (roof repairs), the same ad from the same ad group will show for (roofing companies), (roofers), (ceiling repairs), and other services you may not provide. Exercise serious caution when using broad match keywords or avoid using them altogether (see BMM below). These keywords operate off of a scoring algorithm, and the more key phrases you use, the less relevant they become. For example, we had a moving company as a client and used the broad match keyword (long-distance moving companies). Google chose to show our ads for (long distance phone companies). The reason Google did this is because we used three of the same words (long-distance-companies). Typically, you will find that broad keywords have the lowest conversion rates and the least relevance. The primary purpose of broad match keywords is for keyword research when you are first learning about a new market or when you want to go on a keyword mining expedition. Use the Google Search Query Report (SQR) to mine these new keywords.
Broad Match Modifier (BMM) (some control)
With this match type, you can add a modifier (+) to your broad match keywords (i.e. +roofing +company). This will fire your ad when someone searched for close variants of your keywords in any order, including misspellings, singular & plural forms, abbreviations, acronyms and stemmings. The modifier excludes synonyms and related searches, giving you a higher level of control. These key purpose of broad match modifier keywords is for keyword mining. This is because everywhere that you use the “+” symbol, it requires that keyword to be present.
Phrase Match: (more control)
Fires your ad for searches containing your exact keyword, or your exact keyword with additional words before or after it. Google will also show your ad when someone searches for close variants, or with additional words before or after it. To use phrase match, simply surround your keywords with quotation marks.
Exact Match (full control)
Your ads appear for searches that match your exact keyword without any additional terms. They will also appear for close variants (misspellings, singular/plurals, acronyms, stemmings, abbreviations and accents. To use exact match, surround your keywords with brackets. If you chose highly relevant keywords for exact match ad groups, these groups should contain the highest keyword conversion rate. You will often find that these keywords have a lower cost per acquisition (CPA) than other match types.
Use this match type when you want to filter out certain search terms to prevent unwanted clicks. Your ad will not fire if a search query contains the keyword(s) you define with a minus sign (-) prefix. For example, a residential roofing company might have the words “commercial,” “industrial,” “office” and “building” as negative keywords to avoid getting clicks intended for a commercial roofing company.
This simple chart below, created by Google, makes it easy to understand each match type:
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Next, learn about Keyword Mining with Search Query Reports (SQRs).