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



What is a false negative?

We define a false negative as any email address that successfully passes our verification tests during a flossing process but ends up being an address that bounces when an email is sent to it.

Our Aggressiveness Options are designed to allow you to choose how aggressively you want to floss. With Normal mode, you'll keep more subscribers as we do not run our full gamut of tests, but as a consequence, you may have an increase in false negatives and see them reflected in the bounce rate. We believe this is a sensible option and recommended for most users, as flossing more aggressively will reduce the bounce rate but will also potentially remove more deliverable email addresses than is needed (it may remove too many false positives).

Related: 

In cases of a high bounce rate, you may wish to floss more aggressively. 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. Please note that we suggest using Aggressive as a temporary measure only, and to ultimately go back to Normal mode once the bounce rate has lowered.

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, unless you reach a considerably high bounce rate at 7-8% or above, we recommend keeping Normal mode activated, which is a much more sensible option and allows you to keep the most part of your real subscribers, with fewer false positives on your flossing results.