Former U.S. Secretary of Defense Donald Rumsfeld statement from 12 February 2002, Department of Defense news briefing.

RCA Universal Concepts

Before discussing RCA’s third and fourth steps I’ll again share the figure I include with my March article. Successful RCA includes eight primary elements. Figure 1 illustrates the primary RCA process steps.

Fig 1. Common elements shared by effective RCA processes.
Steps 1 & 2 Refresher. Define the Problem and…

Cause: Stabbing balloon with nail. Effect: A popped balloon.
What is root cause analysis?

Root cause analysis (RCA) is the term used to describe any of various systematic processes used to understand why something is occurring or has occurred. In this post and several that follow, I’ll focus on an approach that I have found to be useful over the years. Regardless of the specific tools used effective RCA includes both subjective and objective elements. The term root cause is often…

John Cleese and Michael Palin of Monty Python’s Flying Circus in the “Dead Parrot Sketch”, first aired in December 1969.What is a dead microbe and why might we care?

I today’s post, I’m returning to a topic I first discussed in 2019 (https://biodeterioration-control.com/2019/07/). In the Monty Python’s Flying Circus “Dead Parrot Sketch”, John Cleese plays the role of an unhappy customer who believes that he has just purchased a dead parrot. Michael Palin – playing the…

Electron microscopy image of the SARS-CoV-2 virus.
 

COVID-19 Infection Statistics

Although anti-COVD vaccines are rolling out and people are being immunized, as of early late December 2020, the rate at which daily, newly reported COVID-19 cases has continued to rise (Figure 1). In my 29 June 2020 What’s New article I discuss some of the limitations of such global statistics. In that post, I argued that the statistics would be more meaningful if the U.S. Centers for Disease…

Meme from the 1986 movie, Heartbreak Ridge (Gunnery Sergeant Thomas Highway – Clint Eastwood – is providing sensitivity training to his Marines).

The Confusion

Over the past several months, I have received questions about the impact of test method sensitivity on control limits. In this post, I will do my best to explain why test method sensitivity and control limits are only indirectly related.

Definitions (all quotes are from ASTM’s online…