If you’re in line for a coffee at the local Starbucks, analysis conducted by graduate students at Rutgers University suggests that the probability of waiting more than five minutes for your tall, hot, three-pump, sugar-free vanilla, one-pump mocha, half-soy, half-nonfat latte with whip is very high.
Brandon Theiss and Matthew Brown used a reliability engineering project to combine their passions for Starbucks’ coffee and gathering and analyzing data with Minitab Statistical Software.
Theiss drew on his work experience in crafting the study. Currently a principal industrial engineer at Medtronic, he previously was a Six Sigma Master Black Belt at American Standard Brands, and a systems engineer at Johnson Scale Co. In 2010, the American Society for Quality named him one of its Top 40 Leaders in Quality Under 40.
“Virtually anything can be characterized as a process and measured,” Theiss says. “Once you have the data, you can use a tool like Minitab to draw conclusions and hopefully improve the process.”
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Comments
Bad example of a capability study
What a pity that there was NO further analysis whether this is a stable process (control chart), nor it was indicated that it was a homogeneous process. The basic mistakes for performing a capability study.
Overanalysis
That really seems like a lot of technically correct overanalysis.
How does any of that analysis fix anything? I guess that's why I've never gravitated toward Six Sigma.
In the complete analysis
In the complete analysis which I will gladly send you a copy of, there are several control charts which represent that the process is stable over the observed time period.
In regard to homogeneity, the premise was that an arbitrary person walking into the given Starbucks. Their experienced wait times based upon the data collected were fairly well modeled by a gamma distribution. Clearly from the small sample size there are confounding factors that were not studied as it was not the intent to be a comprehensive study. It was merely to serve as an example that the same tools techniques and methods that are used to study complex manufacturing systems can also be used for something as apparently trivial as waiting in line at Starbucks.
Further Analysis
Would you be able to send me a copy of your full data. I would love to take a deeper look into this in my spare time.
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