How to analyse Apps KPIs?

Dear experts.

How to analyse Apps KPIs, like accessability, KPIs degradation in LTE?

I think it’s related to Core end KPIs, not radio interfaces domain.

Was it a sudden degradation or gradual degradation?

Gradual degradation in trend.

If degradation with trends, need to trace each part :

  1. Cell contributor, find the cell contribute for degradation.
  2. Cause contributor, find which failure contributor most.

I’m not getting any KPIs degradation in Radio Frequency end.

All KPIs are normal in trend.

Is it happening to an specific TAC?