Proper YTD PPM Supplier Calculation

K

kyoshin_man

Have a question on how to calculate a suppliers ppm for the Year To Date calculation.

We report the monthly ppm rating of our suppliers and have a few individuals argument on how to calculate a YTD figure for them.

Is there an exact method on how to do this? Do you just simply add each months ppm of that supplier and divide by the number of months reported?

Appreciate help and comments to this.
 
J

Jon Nonns

Have a question on how to calculate a suppliers ppm for the Year To Date calculation.

We report the monthly ppm rating of our suppliers and have a few individuals argument on how to calculate a YTD figure for them.

Is there an exact method on how to do this? Do you just simply add each months ppm of that supplier and divide by the number of months reported?

Appreciate help and comments to this.
This will be an accurate measurement only if the supplier has a constant number of parts per month supplied and utilized. Otherwise you are calculating simply an average monthly PPM and not a YTD PPM. The YTD PPM would be calculated as (# defective parts)/(# of million parts suppplied).
 
K

kyoshin_man

Hi,

Yes I agree exactly, since they do not deliver the same qty, then will have to know each qty of each part number supplied. Have argued this till blue in my face, thanks for your advice, very helpful.
 
J

Jon Nonns

Hi,

Yes I agree exactly, since they do not deliver the same qty, then will have to know each qty of each part number supplied. Have argued this till blue in my face, thanks for your advice, very helpful.
Hi, I know how it goes to argue these things repeatedl;y. I recommend that youpropose to either call it what it is (average monthly PPM YTD) or that you show them the math behind the calculation (simple in this particular case) and let them see why it is wrong. Sometimes teaching is the best way to overcome hurdles.
 
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