How to check the quality of back links ?

[omkarsoft]

Identify as many linking root domains as possible using various backlinks data sources.,Check the ToolBar PageRank (TBPR) for all linking root domains and pay attention on the TBPR distribution,Work out the percentage of linking root domains that has been deindexed,Check social metrics distribution (optional),Repeat steps 2,3 and 4 periodically (e.g. weekly, monthly) and check for the following:
A spike towards the low end of the TBPR distribution
Increasing number of deindexed linking root domains on a weekly/monthly basis
Unchanged numbers of social metrics, remaining in very low levels