The quality of a backlink is based on several factors, with the main being:
- Domain Authority
- Page Authority
- Spam Score
- Relevancy
For the first 3 measurements you can get an estimate through the Moz Backlink Checker and it will help you filter damaging domains. Firstly you will need to focus more on the Spam Score, which is based on several factors calculated by Moz. Low Domain Authority and Page Authority aren't on itself a reason to disavow a backlink, but along with a high spam score or is posted on a page with irrelevant content then it can do more harm than good. My personal choice is disavowing most of the backlinks with a spam score of 50-70% and higher, and most of the backlinks with a low DA/PA and a spam score of over 20%.
Relevancy is the most difficult to maintain because it requires you to manually inspect every link and check their content. If your website is regarding construction and you have built backlinks on a gucci bags vendor it will do nothing to improve your rankings, or even harm them.
The geo-location of the site where the backlink is posted is very important for some businesses as well, given that they operate within a certain region. If you're operating within the US there would be no point in having backlinks in Italian or Chinese sites, and ranking on those regions, and from my experience it tends to lower rankings in the origin country. Backlinks on sites without a specific geo-location are fine though.
When selecting which backlinks to disavow you will need to be very careful not to disavow backlinks that are useful to your site and all the above factors need to be taken into consideration altogether.
Daniel Rika - Dalerio Consulting
https://dalerioconsulting.com/
info@dalerioconsulting.com