Dive Summary:

• Test several calls to action (CTA) to make sure that you choose the strongest and remember that results may differ across platforms and audience segments.
• When analyzing test results, look at both the click through rate (CTR) and the bottom line conversion rate equally because, while CTRs are often a good indicator of conversion rates, this is not always the case.
• To look at CTRs and conversion rates together, multiply the two numbers and divide them by 1,000 set impressions.

From the article:

All good search engine marketers (SEMs) know that call to action words (CTAs) play an integral role in developing compelling ads. They also know it’s difficult to determine which CTAs to use.

To make the task even more challenging, CTAs tend to perform differently across verticals, so there is not a one-size fits-all approach for selecting the highest performers. For example, the best performing CTAs for a financial services advertiser ("analyze," "trade," "sign up for," "open an account,” etc.) might be completely different than those for a clothing retailer ("buy now," "order,” “purchase,” etc.).

To help determine which CTAs to use in your various campaigns, you need to know how to properly analyze the performance. ...