What's a false positive and why is it a risk?



We define a false positive as any email address that fails at least one of our verification tests during a flossing process with a category reason of either "nonexistent", "deactivated", "inbox_full", "unverified", or "accept_all" but ends up being an actual address that poses no risk to your list.

For example, if we mark an email address as "inbox_full", it means at the time we ran the test this email address had a full inbox. It's very possible that by the time you email this address, the owner of the inbox could have cleared space in their inbox, thus allowing the email message to be delivered.

 And the hardest false positives to detect, by far, are those in the "accept_all" category. If an email server is set up this way, that means *every* email address in this domain will be categorized "accept_all", including the perfectly valid email addresses from this domain. While our proprietary Deep Clean engine is the best in the business at detecting real and fake "accept_all" email addresses, it isn't perfect and there will still always be some false positives as a result.

Our Aggressiveness Options are designed to allow you to choose how hard you want to floss. With Aggressive mode, you are bound to have a higher false positive rate but a lower bounce rate mainly because of the previously discussed "accept_all" category.

As such, we recommend Aggressive mode only temporarily until your bounce rate lowers to acceptable levels. There's a "help me decide" link beside the Aggressiveness options that you can click on to help you decide if Aggressive might be the preferred option until the bounce rate has lowered.

Why do we recommend Aggressive only temporarily? 

Because you may be losing valid/deliverable email addresses being automatically unsubscribed and deleted from your account during your flossing sessions that are false positives. This is exactly why we don't recommend having Aggressive mode selected in your integrations at the same time as an automated mode like Autofloss or Instafloss, and other automatic options such as Auto-unsubscribe or Auto-delete (remember that both options are irreversible).

At the end of the day, our mission at mailfloss is to help you maintain a clean and healthy list, without sacrificing all those hard-earned leads and subscribers. That's why once your bounce rate is down to acceptable levels, we recommend switching back to Normal, which is a much more sensible option. Your bounce rate may increase, but there will be fewer false positives.