As keyword lists expand, they often outgrow the groups that were initially created to contain them. For example, a group that started out with a single keyword, [running shoes], could expand over time to contain [running shoes], [womens running shoes], [jogging shoes] and [black running shoes], among others.
The original creative that was generated to match [running shoes] queries would be less relevant to the newly expanded keywords and, as a result, the overall click-through rate (CTR) of this group would decline.
This decline in group CTR, as keyword count increases, exposes a useful [...]
Related Topics: Channel: SEM | Enterprise SEM