You are leading a brand awareness campaign for a car company, and you’d like to create buzz for your new model. Which metrics do you need to look at in your reports?
Clickthrough rate and cost-per-click
Conversion delay and cost-per-acquisition
Impressions, reach, frequency
Impressions and conversions
Once you’ve established your branding campaign’s goals, you can choose the best places to show your ads, and then measure success by monitoring impressions, conversions, and other statistics. Reach is the number of visitors exposed to an ad. Increased reach means that an ad is exposed to more potential customers, which may lead to increased awareness. Frequency is the average number of times a visitor was exposed to an ad over a period of time.
Read more here: //support.google.com/adwords/answer/1722064