I built two reports in the Custom Reports section. The first is Email Campaign Performance Data By Day and it allows me to select message name, and the the unique sum and total sum of opens and clicks. The second is Email Engagement by Campaign Report and it shows a single line for every campaign with the same metrics (unique sum and total sum of opens and clicks). When I aggregate the unique opens by email campaign name in both reports, the totals do not match. Is this because the Unique count in the By Day report is showing the same person multiple times if they returned on a different day? Whereas the email engagement by campaign report shows the total unique count of people that opened the email?
If this is the case, how can I extract the Email Engagement By Campaign Report data via API?