Hi Lindsay, are you using an email program, and the "audience" number is from the email program dashboard? I have found email programs to be very quirky/finnicky, and the dashboard doesn't always display the right number of people who will receive the campaign. Also, are any of the 800 people you're missing marked as email invalid, unsubscribed, or marketing suspended? If this isn't the case, you might set it up as a smart campaign and see if you would impact the correct number of leads.