Jul 31 2021

Follett in 1924: Use Operators’ Knowledge

Mary Parker Follett

 

Almost 100 years ago, Mary Parker Follett wrote: “And our aim in the […] organization of industry should be […] so to organize the plant that the workmen’s experience can be added to that of the expert; we must see just where their experience will be a plus matter, and we must plan to have the workmen learn more and more of the industry as a whole.” 

Source: Follett, M. P. (2013 reprint). Creative Experience. United States: Martino Fine Books. (p. 20)

Michel Baudin‘s comments: Today, we would say “manufacturing” rather than “industry,” and “operator” rather than “workmen.” This is the earliest text I have seen that recommends engaging shop floor operators in improvement activities and training them to understand the broader picture. 

Taylor wanted to control operators so that they couldn’t collude to curtail output. The Gilbreths wanted to make their work easier. Follett wants to tap into their knowledge and combine it with the experts’ in order to achieve better outcomes. And she also believes in their ability to learn.

In these few words, she showed more respect for the humanity of the operators than I recall seeing from her immediate precursors and contemporaries. 

 

#maryparkerfollett, #respectforhumanity, #traceyrichardson

 

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Jul 30 2021

Sales Forecasts – Part 2. More About Evaluation

The lively response to last week’s post on this topic prompted me to dig deeper. First, I take a shot at clarifying the distinction between point forecasts and probability forecasts. Second, I present the idea behind the accuracy metric for probability forecasts that Stefan de Kok recommends as an alternative to the WSPL. Finally, I summarize a few points raised in discussions on LinkedIn and in this blog.

All of this is about evaluating forecasts. We still need methods to generate them. There are many well-known, published methods for point forecasts but not for probability forecasts, particularly for sales. This is a topic for another post.  

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Sales Forecast Example

Jul 16 2021

Sales Forecasts – Part 1. Evaluation

When sizing a new factory or production line, or when setting work hours for the next three months, most manufacturers have no choice but to rely on sales forecasts as a basis for decisions.

But how far can you trust sales forecasts? You use a training set of data to fit a particular model and a testing set of actual data observed over a time horizon of interest following the end of the training set period. The training set may, for example, cover 5 years of data about product sales up to June 30, 2021, and the testing set the actual sales in July, 2021. 

The forecasters’ first concern is to establish how well a method works on the testing set so that the decision makers can rely on it for the future. For this, they need metrics that reflect end results and that end-users of forecasts can understand. You cannot assume that they are up to speed or interested in forecasting technology.

Forecasters also need to compare the performance of different algorithms and to monitor the progress of an algorithm as it “learns,” and only they need to understand the metrics they use for this purpose. 

 

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Apr 16 2021

Measuring QC Efficacy: A Proposal

[The featured image is of a Vietnamese satellite undergoing final test in Japan]

As Jay Bitsack pointed out in his comments on LinkedIn about my previous post, the portability of a method from epidemiology to manufacturing quality is not a foregone conclusion. Formally, the logic of validating a vaccine seems applicable to the solution of a quality problem. They look similar when you consider only outcomes in terms of infection rates or the proportion of defectives. 

There are differences between data sets from a clinical trial and tests run before and after a process change in production that may affect the applicability of a method. We examine the conditions for the approach developed by Carlo Graziani for vaccine efficacy to cross over to quality control. Then we work out the math of Graziani’s method and the means to apply it. 

 

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Apr 2 2021

COVID-19 Pfizer Vaccine Study On Teens

Pfizer-BioNTech just announced the results of a COVID-19 vaccine clinical trial of 12- to 15-year olds. Because the vaccinated group had 0 infections, the news media jumped to the conclusion that the vaccine has “100% efficacy” on 12- to 15-year olds. That is what the chyron said on NBC news. A look at the published trial results and quick analysis with current methods confirms that the vaccine works for that population but not that it eliminates 100% of the infections.

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Mar 12 2021

Process capability

The literature on quality defines process capability as a metric that compares the variability of its output with tolerances. There are, in fact, two different concepts:

  1. The ability of a process under nominal conditions to consistently produce output that meets expectations.
  2. The means of assessing it.

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