Your client wants to increase the number of people visiting his website. When analyzing the data for his Search campaign, which metric do you most want to improve?
Clickthrough rate (CTR)
CTR is a ratio showing how often people who see your ad end up clicking it. CTR can be used to gauge how well your keywords and ads are performing. A high CTR rate is a good indication that users find your ads helpful and relevant. It’s one of the most important indicators analyzing your marketing campaigns.
Different metrics available on AdWords will be less or more important depending on your goals and particular campaign.
A clickthrough rate shows how often people who see your ad end up clicking it. It’s an important metric if you want to know how your ads are performing or if people find your ad appealing. If you want to improve the number of people visiting your site, the first metric to improve is CTR. The higher CTR, more people visit your site.
CTR is the number of clicks that your ad receives divided by the number of times your ad is shown: clicks ÷ impressions = CTR. For example, if you had 10 clicks and 1000 impressions, then your CTR would be 10%. CTR will depend on many aspects like targeting, industry, placements, keywords, network, ads etc.
Read more here: https://support.google.com/adwords/answer/2615875?hl=en