By Kye Mou June 20th, 2012

As keyword lists expand, they sometimes out-grow the groups that were initially created to contain them. For example, a group may have started out with a single keyword, “running shoes”. However, after some time and a little keyword expansion, that same group now contains the keywords “running shoes”, “womens running shoes”, “jogging shoes” and “black running shoes”, among others. The original creative that were generated to match “running shoes” queries are now less relevant to the newly expanded keywords. As a result, the overall click-through rate (CTR) of this group has declined. This decline in group CTR, as keyword count increases, leads to a useful metric that should be considered when optimizing creative: keywords per group.

Groups with a higher number of keywords often have lower CTRs and lower Quality Scores than groups with a concise and focused set of keywords. This is because the creative within densely populated groups can only leverage a subset of its keyword’s tokens for maintaining relevance. In our example above, the creative leveraged the token “running” rather than “jogging” to maintain relevance to “running shoes” queries.

To identify and prioritize groups for creative optimization, generate a data table containing the number of keywords, CTR and cost of each group in the account.

Then create a bubble chart to plot the relationship between the three metrics.

Take note of the larger circles in the lower right hand corner of the bubble chart. These groups should be prioritized for optimization. Locate and break out less relevant keywords within these groups into new groups that contain more relevant creative. In our example, “jogging shoes” should be split out into a Jogging Shoes group with creative that utilize the term “jogging” rather than “running”. Executing on these best practices will lead to improvements in CTR and Quality Score.

Keep in mind that Quality Score will reset for the keywords that are split out into new groups. Allow an initial burn-in period for these new keywords to establish their own Quality Score before evaluating performance. As a best practice, check the status of each keyword and ensure that its bid is set above the first page minimum. Give these bids an initial boost to increase ad position. A higher ad position promotes a higher CTR, which remains a significant factor in improving Quality Score.

To help generate the data table and bubble chart above, Marin users can leverage the Active Keywords metric under the Advanced group column category. Be sure to tag the split keywords and affected groups with Dimensions to monitor performance. Finally, don’t forget to optimize the newly created groups; setting appropriate keyword bids, generating relevant creative and researching negative keywords are just a few strategies to in mind.