You are interested in understanding how campaigns are driving traffic to your site. What metric would you look at to see how often people who see your ad end up clicking it?
- Clickthrough rate
Explanation: A ratio showing how often people who see your ad end up clicking it. Clickthrough rate (CTR) can be used to gauge how well your keywords and ads are performing.
Read more here: https://support.google.com/partners/answer/2615875