Marketing Insights
Marin Software's Official Blog

Keyword Expansion

By   September 2nd, 2011

Keyword expansion is a generalized term for increasing the keyword count for a search ad campaign. There are many tools for generating keyword expansion recommendations including Adwords, Adcenter, and Marin’s own proprietary keyword expansion tool which has the additional functionality of being able to track conversions associated with raw queries to provide better insight into whether keywords make sense to be added based on their post click success.

Keyword expansion is one of few optimizations that has the opportunity to increase volume while decreasing CPC’s. Keyword expansion can be used to increase reach, improve campaign efficiency or both. The impact of keyword expansion, whether to increase efficiency or volume, is generally determined by whether expansion is being done on existing keywords or new keywords. Existing keywords can be optimized by expansion of more efficient match types; this strategy is effective in increasing campaign efficiency. New keywords can be created through keyword expansion to capitalize on increased reach; this strategy is effective in increasing campaign volume and can also increase efficiency.

Existing Keywords

Expansion of existing keywords through the use of match type parity is typically executed to channel click traffic from less efficient, broad and/or phrase match types, to more efficient, phrase and/or exact match types. As broad match keywords can bring in more irrelevant and unknown queries than phrase or exact match counterparts they also tend to have lower conversion rates. The more targeted match types are also likely to display ad copy that has increased relevance to the captured query which should result in increased CTR’s, better quality score and lower CPC’s.

As new campaigns are created this practice of match type parity can be used proactively to achieve efficiencies immediately.

If a keyword is running in a Google campaign on all three match types Adwords will still drive queries to broad match keywords if the broad match bid exceeds that of the phrase and exact match types of the same term. For this reason, when expanding keyword match types in Google it is recommended that separate groups be created for each match type so that negative keywords can be used guarantee queries be driven to more efficient match types.

  • Google broad match group – Phrase match negatives
  • Google phrase match group – Exact match negatives

New Keywords

Expansion of new keywords can be used to generate additional volume by increasing a campaigns reach or can identify phrase and/or exact match keywords that can be added to improve efficiency.

Broad Match Expansion:

Keyword expansion of broad match terms can be coined as “exploratory spend,” this term signifies that increased spend can be applied through the expansion to identify opportunities that are not currently being taken advantage of. Exploratory spend can be applied to head terms (low token count) or tail terms (high token count) depending on the desired results.

  • Head Terms – can be used to generate a large pool of keyword opportunities in a short timeframe.
  • Tail Terms – can be used to generate a smaller but more relevant pool of keyword opportunities.

Either keyword expansion option should be further refined by mining raw query reports to determine what queries are effective which can be added as more efficient match types. Queries identified as inefficient represent opportunities for negative keywords that can be used for further refinement and efficiency.

As the addition of broad match keywords could significantly increase traffic and spend it is often advisable to create and exploratory spend campaign so budgets can be managed separately from normal traffic. It is recommended advertisers account for match type parity when implementing keyword expansion for exploratory spend to realize any potential efficiencies immediately. This exploratory spend can be an effective way to increase spend and clicks as budgets increase, or explore potentially more efficient keywords while maintaining budget levels.

Exact/Phrase Match Expansion:

Keyword expansion of phrase and/or exact match terms provides similar opportunity to the match type parity explained above. Similar to the recommendation of having a broad match keyword paritied to phrase and exact match types, all search queries (or converting search queries) that are generated by a broad match keyword represent an expansion opportunity. Broad match queries can be added to a campaign as a phrase and/or exact match keyword(s) to ensure future traffic generated by the query will be channeled through the more efficient and relevantly targeted match type(s).

As existing campaigns progress through their lifecycle of optimization and refinement, advertisers should expect to see an increased percentage of ads spend transitioned from broad match keywords to their more efficient counterparts. Below is a list of common keyword expansion strategies:

Keyword Expansion Opportunities
• Plurals
• Geographical targeting
• Modifiers
• Category keywords
• Business name keywords
• Misspellings
• Brand keywords
• Seasonality keywords
• Jargon keywords, nicknames, and acronyms
• Question keywords