I have to post this. Apologies if it ruffles the Black Belts among you but this is precisely why clients aren’t interested in the boffin levels Sigma go to. They want a continuous improvement culture not the equation to calculate the trajectory of Apollo13…..I mean, it’s for a call centre environment, one of the most chaotic set of processes. A pragmatic approach is really all that’s needed here yet sometimes we are so caught up in our own ideals we fail to see that a simple answer might be the best.
This appeared on LinkedIn today:
I Need a help to solve this Six Sigma Case, for many it might be easy
Case:There is a Call Center process in which CTQ is Customer Response Time.If Customer Response Time is more than >60sec then its a defect.In this Case opportunity will be 1.Suppose there are 300 Calls and out of that 123 call Response time is >60 sec(This is defect) and opportunity is 1 then my Sigma value will be 1.727.This value came by this Formulae
process Sigma = NORMSINV(1-((Total Defects) / (Total Opportunities))) + 1.5 and DPMO is 410000, this value came by this formulae
Defects Per Million Opportunities (DPMO) = ((Total Defects) / (Total Opportunities)) * 1,000,000
Question is, Can anybody tell me from this case how can i get bell Curve.How i should calculate USL and LSL value.How i will draw this Bell Curve in a excel.Waiting for all your master response?
An excellent response from a friend over at the BPM Nexus and paraphrased here sums it up:
“…at the end of the day if you produce a bell curve telling me the USL and LSL for my call centre, along with the number of defects per million and a sigma value of 1.727, is this really a useful measure? More to the point, what can I – as a business person – do with it?”