- historical cost-per-click (CPC) estimates for your keyword and placement ideas
- traffic estimates for your keyword ideas
- traffic estimates for placement ideas
- historical conversion rate estimates for your keyword and placement ideas
Explanation: Each idea comes with impression estimates and historical costs. Think of these estimates and statistics as a guide to help you plan your Display Network campaign, rather than to project future performance.
Read more here: https://support.google.com/adwords/answer/3056153?hl=en