Is PPM a good metric for gathering companywide complaints ?


Starting to get Involved
Greetings Cove Friends!

I work for an apparel company, prior to my arrival they gathered complaints from 3 different departments separately; production, customer service and packaging/shipping. These are all calculated in PPMs, productions is compared to what they produced for the month and customer service and shipping is compared to the number of pieces invoiced.

My issue is, we are ignoring complaints from other departments giving us a false sense of security in our PPMs. We can get complaints from accounting, design, graphics and a few other departments. There is a tracking mechanism so I am able to gather the complaints from the other departments, I'm just wondering how to compare total complaints like this to derive the PPM. Would you use number of pieces invoiced or total produced. Something to consider is our sewing floor may produce more product than what was invoiced because we sometimes add to shelf stock than send directly to the customer. Or is there another metric that I could use? My goal is to provide not only a department metric but also a company wide metric.

Thank you in advance!

Jen Kirley

Quality and Auditing Expert
Re: Gathering Companywide Complaints

Good morning melissa,

I do not feel sure that ppm is the best metric for everything. If I understand your reference correctly, it is "parts per million" and as such relies on a large number of transactions, items sold or opportunities for error. Where the numbers are smaller, could a simple ratio work?

I am also wondering if everything is to be given the same level of importance as ppm, which started out as a metric for manufacturing (usually low cost) widgets. Where a single lost customer or line error in accounting can exceed the cost damage of a thousand defective widgets, why not raise the threshold of some metrics just based on management interest?

A balanced scorecard such as this image from the internet can provide you the flexibility and format to track multiple things at once. Your organization can set the formulas and thresholds, and indeed as you get better the formulas and thresholds could change to reflect the "tightening" of controls and better outcomes.

I hope this helps!

Bev D

Heretical Statistician
Super Moderator
I am not put off by the use of ppm as it really is nothing more than using a % except the multiplier is different. Jennifer has a good point about scale tho. If the occurrence rate is large enough a % or simple proportion should suffice. If the occurrence rate is very small, ppm is a suitable adjustment of the proportion.

Jennifer is also correct that you might want to assess the severity of the defect/error in your metric. This is usually done with some type of Cost of poor quality assessment or weighting depending on the effect on the Customer work flow or loyalty...although these can be somewhat more complicated to implement, so if you are just getting started and people understand that the goal is to continually improve the occurrence rates of defects/errors then it might be sufficient to start with a simple occurrence rate.

Your denominator should be the number of opportunities for the specific type of errors or defects and this always varies by department. for accounting its number of invoices (or statements) for shipping it may be line items or packages or orders. it gets messy quickly.

I would suggest that you search for the phrase perfect order metric. it is a holistic metric for what I think you are trying to do - at any rate it may give you some ideas...
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