The Deliverability Score is the accuracy score of the emails presented on your account.
Each user in an account can set their individual deliverability score of the emails they receive when revealing or exporting contact details.
Emails with a Deliverability Score of over 80% are more accurate and have a lower bounce rate.
Emails with a score below 80% are based on statistical recommendations. If you set the Deliverability Score under 80%, you will get a higher email coverage (more emails presented), but high bounce rates may occur.
When the ALL option is set as the Deliverability Score all contacts are revealed, even those with only social links, if no email or mobile phone is available.
To change your Deliverability Score click on the Settings icon 
on the left navigation bar.
On the Profile tab go to the User Preferences section and open the drop-down menu to choose the relevant Deliverability Score:
After you have made the relevant changes, click on Save Changes.
Please note that this will not impact or change the Deliverability Score set on other users in your account (in case there is more than one user in your account).