New Lead and New Contact in Campaign Engagement in Insight

Hi, I am interested to understand the metrics in campaign reports for New Leads and New Contacts. When I run a report, it returns a large number of New leads and new contacts. When I look at the contact records in Eloqua, many have a created date before the campaign response. In some instances, a New Lead is displayed in 2 campaigns. I am trying to understand the true value of these metrics.

Thanks.

The metric definitions provided by Eloqua are as follows:

New Contacts
The total new contacts. A contact is considered new if the contact record was created as a result of a campaign response. Your organization defines what a response is and the priority of the response using response rules.