The Broken Quality Bookshelf
The Broken Quality Bookshelf serves as a repository for essays and case studies on the topics of Statistical Process Control (SPC), process behavior charts (control charts), and applied data analysis. The datasets and code associated with the essays found below can be found here. If you have questions regarding any of the essays or are interested in contributing to The Broken Quality Initiative send us an email at TheBrokenQualityInitiative@gmail.com.
Quality has become an overused term of little substance. This essay elucidates how the current state of quality came to be and what we can do to fix it.
What is a spec limit? What is a process limit? This essay articulates operational definitions for process limits and spec limits and the context for the use of each.
Theory
Without context, data is random and miscellaneous. This essay articulates how process behavior charts establish context and imbue meaning.
Process behavior charts allow us to anticipate the future based on the past. This essay provides an example of how to achieve this using inspection data.
The process capability indices are a standard method by which process performance is graded. This essay explains these indexes and puts their use in context.
Supplier Quality
Modern manufacturing ecosystems produce data at a scale unrivaled in human history. Network analysis expands the utility of SPC to make sense of that data.
Application
On-Time Delivery (OTD) is a common supplier quality metric. This essay expands on the utility OTD using a novel SPC approach called network analysis.
Manufacturing in modern industry is often executed across global networks of suppliers. This essay outlines an alternative method for understanding supplier quality.
Process behavior charts are often seen as useful only in manufacturing. This essay is an example of how the utility of process behavior charts extends to other domains.
Same parts, new supplier, no problem! This essay serves as an example of how to evaluate existing parts made by a new supplier using process behavior charts.
Modern business and industry has developed a detrimental relationship with PowerPoint. This essay explains how written reports can deliver us from this evil.
Calculating process limits and build process behavior charts is an exceedingly rare skill. This essay teaches readers how to build PBCs on their own.