Thermometer, Thermostat, or Smart Thermostat? Supply Chain Quality Approaches

By John McGlinn
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What can the seemingly straight-forward tools we use to regulate temperature tell us about our approaches to supply chain quality?

The seasons bring with them our sensitivity to weather conditions, and especially to how hot or cold it is, inside or out. We measure those conditions, and we try to regulate them so that we can stay within a safe and comfortable range. In many ways, the processes we use to do these things have analogies in the world of Quality Assurance. What can the seemingly straight-forward tools we use to regulate temperature tell us about our approaches to supply chain quality?


The definition of a thermometer is “a device that measures temperature or a temperature gradient, using a variety of different principles.” Two components are required: it must be able to sense the temperature and any change in it, but then it must also convert that information into some kind of scale using numbers. A key property is standardization, especially when regulating production processes. There should be nothing subjective about a temperature reading. Without standardization and agreement on the scale to be used, the readings are meaningless.

While a thermometer is critical to many production processes (not to mention in medicine, weather and scientific research) it has, by design, some limitations. 1. A thermometer does not initiate a reading. Someone decides to use a thermometer at a certain time to get a reading. In this way, a thermometer is a highly effective, yet passive instrument. 2. It shows a snapshot of what is happening at the moment of the reading. 3. It does not show any comparisons to what happened before, or what comes after, unless it is integrated into a system that goes beyond being the technology of the thermometer, i.e., beyond the” bulb” and the “mercury” it contains.

Supply chain quality tools: Audits and self audits

The analogue to the thermometer in the world of Quality Assurance is an audit. An audit is initiated by some agent (management, legislative enforcement, voluntary compliance with industry standards). Someone or something then takes the “temperature” of a process at some moment in time. It shows just that – what is happening at the moment. It makes the assumption that the next moments in time, until the next audit, will be just as “healthy.”


Rather than a self-contained tool (like a thermometer), a thermostat is a part of a control system. The system has the capacity to sense the temperature of a system, and respond in such a way that the system returns to a certain level, a “set point.” When it senses an anomaly, it responds by switching on either the heating or cooling components, or by regulating the flow of heat transfer materials.

Supply chain quality tools: Reports

The analogue to a simple thermostat in the supply chain quality world is an assortment of reports. They include information that is collected, such as:

  • Certificates of Analysis (COA)
  • Certificates of Compliance (COC)
  • Dynamic questionnaires
  • PDF Forms
  • Certifications

When the reports show that, at that moment, things are “too hot” or “too cold” (in other words, out of specification), then the system responds to what is collected with:

  • Corrective action plan
  • Material specifications, whether new or adjusted
  • Purchase order information
  • Supplier nonconformances
  • Supplier scorecards
  • Supplier rankings
  • Supplier processes (to be used)
  • Supplier procedures (to be used or changed.)

It’s clear that the system is set up to respond. However, it also means that the system may swing between various points of being outside the range of necessary specifications, just as a simple home thermostat may be constantly adjusting to return to a desired temperature, although much of the time it is in a condition of “returning to” rather than “at” a specified temperature. Once it reaches that temperature, it immediately begins to destabilize. Once it reaches a certain boundary, the thermostat kicks in to move back toward the “ideal.”

In the supply chain quality management context, this may allow for material variability that is constantly trying to return to a condition of compliance with specifications.

Smart Thermostat

No modern building is without a “smart” thermostat. What makes smart thermostats truly smart is that they reduce the amount of variability. They are so sensitive to changes that the response is quick and decisive. The variability is broken up into very small stages, and even a small increment triggers a quick correction, making the system much more consistent and stable.

Supply chain quality tools: Material variability management and Statistical process control

Just as a thermostat is really a component of a system, Material Variability Management (MVM) is a “smart thermostat” in the domain of supply chain quality management. Electronic documents flowing at a constant rate through a system, powered by Statistical Process Control (SPC), can spot trends and anomalies much more quickly than the large increments that cause a system to constantly react, getting too hot and too cold, while assuming that averaging the two makes the environment pleasantly warm.

Material Variability Management is based on the physical inspection and/or testing of all critical inputs and sub-assemblies in real time, along with specification verification, as well as approval to ship so that no material that doesn’t meet specifications moves through the supply chain. It is a system that integrates an array of tools such as:

  • Specification collaboration/distribution/sign-off
  • Supplier COA test data capture (manual and computer-to-computer)
  • Production batch tests data capture
  • Outbound COA generation from batch test data capture
  • SPC Analyses including individual test trending of out-of-spec conditions and into problem zone (beyond 3 sigma and approaching spec limits)
  • Ship-to-Control visualizations and range setting
  • Alerts for material problem performance
  • ANSI Z1.4 Sampling data capture and analysis
  • Lab test analysis data capture and comparisons
  • Advanced-BI for user-definable reports and dashboards
  • Material and location QA audits

MVM powered by SPC turns a supply chain quality management system into a truly SMART thermostat. Instead of taking a snapshot of reality and reacting to it, it can sense trends and send early warning signals that prevent the entire system from becoming unstable. Your enterprise deserves state-of-the-art support, especially when the technology is affordable, reliable, will save you money, and will secure your reputation for high quality.

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