dgoscinski
New Member
I have a ton of data covering a year. I have to calculate a "Defective Parts per Million." The MONTHLY formula is (#of Defects/Total Sold)*100000. Doing this in a pivot table is not a problem to calculate monthly. What I require though is a running total of the previous 12 months as well.
In other words, the yearly formula should be something like this (# of Defects in the last 12 months/Total of items sold over last 12 months)*1000000.
I can get a running total without issue in a pivot table. However, it automatically adds the month before. I would essentially like to add 11 months before.
I have included a data set WITH pivot table.
Monthly PPM is already calculated.
Here is what I need:
January 2019 PPM would be: (Total # of Defects from Feb2018 to January2019/Total Parts Sold from Feb2018 to Jan2019)*1000000
February 2019 PPM would be: (Total # of Defects from Mar2018 to Feb2019/Total Parts Sold from Mar2018 to Feb2019)*1000000
March 2019 PPM would be: (Total # of Defects from Apr2018 to Mar2019/Total Parts Sold from Apr2018 to Mar2019)*1000000
And so forth.
Basically, the bolded part of the formulas above are where I need help.
A total from previous month in the pivot table ONLY tallies from previous amount. I need the tally to ALWAYS look back over 12 months and only 12 months.
In other words, the yearly formula should be something like this (# of Defects in the last 12 months/Total of items sold over last 12 months)*1000000.
I can get a running total without issue in a pivot table. However, it automatically adds the month before. I would essentially like to add 11 months before.
I have included a data set WITH pivot table.
Monthly PPM is already calculated.
Here is what I need:
January 2019 PPM would be: (Total # of Defects from Feb2018 to January2019/Total Parts Sold from Feb2018 to Jan2019)*1000000
February 2019 PPM would be: (Total # of Defects from Mar2018 to Feb2019/Total Parts Sold from Mar2018 to Feb2019)*1000000
March 2019 PPM would be: (Total # of Defects from Apr2018 to Mar2019/Total Parts Sold from Apr2018 to Mar2019)*1000000
And so forth.
Basically, the bolded part of the formulas above are where I need help.
A total from previous month in the pivot table ONLY tallies from previous amount. I need the tally to ALWAYS look back over 12 months and only 12 months.
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