DescriptionUndefined or not-computed (NC) slack can happen in a design for multiple reasons, for instance dis-connected wires, dis-connected gates, phase-pair excluded tests amongst others. A design has to be NC clean to get a passing grade. Debugging the root-cause of NC slack is however a tedious and time-consuming activity for designers. Timing analysis tool generates a timing NC-report that lists test points where it has NC slack. The problem is that the root-cause of NC slack many a times can be due to an issue upstream of a path and not at the pin reported in the timing report. The root-cause coverage of a timing report can vary wildly---from 68% to 78% in our benchmarking---based on a design. In this work we have developed a netlist design data based solution in Python that looks for those pins that timing NC-report couldn't root-cause and show that the coverage now is well over 97% (and increasing), thus providing significant productivity improvements to designers. The script is deployed and is being used actively by designers.