how to understand it?
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 This topic has 6 replies, 4 voices, and was last updated 16 years, 10 months ago by TipperG.

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January 23, 2006 at 1:07 pm #42093
Enter your process opportunities and defects and press the “Calculate” button.
Switch To: Advanced Mode
Opportunities
Defects
Calculation Results
DPMO
Defects (%)
Yield (%)
Process Sigma
© iSixSigma 20002006
What does it mean? I have 1000000 opportunities, so e.g on 10000 invoices I have the possibility to make 1000000 mistakes. I have 3,4 mistakes in reality, so why my sigma is not 6, but 5,4? Do I understand sth wrongly? Thank you for reply0January 23, 2006 at 1:28 pm #132694
Jered HornParticipant@HornJM Include @HornJM in your post and this person will
be notified via email.Not sure that I understand…”so e.g on 10000 invoices I have the possibility to make 1000000 mistakes”.
If you key in “3.4” instead of “3,4”, the calculator will interpret 3.4 defects per million opportunities instead of 34. That will give you the desired “6” Process Sigma result.0January 23, 2006 at 2:07 pm #132702Enter your process opportunities and defects and press the “Calculate” button.
Switch To: Advanced Mode
Opportunities
Defects
Calculation Results
DPMO
Defects (%)
Yield (%)
Process Sigma
© iSixSigma 20002006
Thank you. Now, what does it mean, that DPMO=3 and yield=100?
0January 23, 2006 at 2:26 pm #132705
Jered HornParticipant@HornJM Include @HornJM in your post and this person will
be notified via email.It’s not really very useful information…
DPMO = 3…That means you can expect 3 defects per million opportunities. The calculator rounded 3.4 to 3.
Yield % = 100…That means you can expect 100 good parts out of 100. The calculator rounded 99.9997 to 100.0January 23, 2006 at 3:24 pm #132713Hmmm,
Let’s take one step back. The numbers you fill in in the fields opportunities and defects is what YOU have measured in YOUR process. When you press on calculate you then get the DPMO, Defect Rate, Yield & Sigma level of your process.
So let us see what the different input terms (opportunity, defect) mean in your context.
From your message I assume we are looking at an invoicing process (seeing you talk about producing invoices).
Now, the most singular output of the process is 1 invoice, so the Product = 1 invoice
On each invoice there are several fields containing information. A field containing incorrect information is called a Defect. (An invoice containing one or more incorrect fields is called Defective.)
The opportunities for a defect is simply the number of fields that can be either correct or incorrect. For the sake of the example let’s assume an invoice contains 10 such fields.
Now let us imagine that over the past month, 10,000 invoices have been produced.
As each invoice has 10 opportunities for mistake, the total number of opportunities is 10 * 10,000 = 100,000
You looked at each invoice and found in total 5,673 fields were incorrect => so there are 5,673 defects
Plug these numbers in the calculator and you get
DPMO = number of defects to be expected if a million invoices are made = ( DEFECTS / TOTAL OPPORTUNITIES ) * 1,000,000 = ( 5,673 / 100,000 ) * 1,000,000 = 56,730
Defect Rate (%) = DEFECTS / TOTAL OPPORTUNITIES = 5,673 / 100,000 = 0.05673 or 5.673 %
Yield (%) = 1 – Defect Rate = 1 – 0.05673 = 0.94327 or 94.327 %
Process Sigma = zscore corresponding with DPMO found above = 3.08
Hope this clarifies0January 23, 2006 at 3:43 pm #132715
Jered HornParticipant@HornJM Include @HornJM in your post and this person will
be notified via email.tipperg,
That is an excellent clarification.
Is this right, though?…
“DPMO = number of defects to be expected if a million invoices are made…”
Shouldn’t it be…”DPMO = number of defects to be expected per million opportunities…”?
Just want to make sure.0January 23, 2006 at 3:48 pm #132716hi HornJM,
yup, your phrasing is the correct one, I forgot about the 10 opps per invoice when I wrote my sentence.
thanks for pointing that out
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