View-through conversions are available only to:
- advertisers that have implemented Conversion Optimizer
- advertisers that have implemented Conversion Tracking
- advertisers that have opted into the Search Network
- advertisers that are using AdWords for Video
Explanation: Once you’ve set up conversion tracking, you’ll have access to a handy set of reports about your conversions.
Read more here: https://support.google.com/adwords/answer/1722023