Posted by Sten Westgard, MS
Posted by Sten Westgard, MS
In the iconic western film, The Magnificent Seven, there is a famous scene about marksmanship. [Quick set up: The Magnificent Seven are - you guessed it, seven - gunmen hired to protect a peasant village from a much larger group of bandits] Early in the film, the heroic gunmen detect three bandit scouts and want to capture them. In an abrupt exchange of gunfire, two bandits are killed, but the third bandit mounts his horse and attempts to escape. As the bandit flees, one of the gunmen, Britt, steadies his pistol and takes aim. The escaping bandit gallops farther and farther away. But just as he is about to disappear behind a hill, Britt shoots, hitting the bandit square in the back, killing him. The youngest of the gunmen, Chico, shouts:
Chico: (in awe) That was the greatest shot I've ever seen!
Britt: (sternly) The worst! I was aiming at the horse.
This scene reminds us that even when what one person thinks is great performance may not be acceptable by another person's standards. Indeed, what appears like an accomplishment may actually be an error.
And what, you may ask, does this have to do with Six Sigma?
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Sten Westgard, MS
[Posted by Sten Westgard, MS, from the AACC Press Release]
Posted by Sten Westgard, MS
Posted by Sten Westgard, MS
As we write, the National Basketball Playoffs are underway. The home team for Westgard QC, the Milwaukee Bucks, just went down to defeat in the final game of a 7-game series.
Those who follow basketball know that in a series like this, the teams basically alternate home court advantage. The Bucks went to Atlanta to play the Hawks for two game,s then the Hawks came to Milwaukee to play the Bucks for two games, etc. But while there is a home court advantage in the audience (which didn't work: both teams won away games), the courts in every stadium are the same. The basketball hoop in Atlanta is the same as the basketball hoop in Milwaukee. Why is that?
Because the rules specify a consistent goal. The NBA has a rule book which states the precise size of the court, equipment and basket size. A basket, for example, "shall consist of a pressure-release NBA approved metal safety ring 18" in inside diameter with a white cord net 15" to 18" in length." Every stadium must comply with this rule.
Likewise, there is a single standard for the basketball: "The National Basketball Association (NBA) allows only one official ball: The ball must be the official NBA game ball manufactured by Spalding. The ball is orange in color, 29.5 inches in circumference and weighs 22 ounces (size 7). It must also be inflated to between 7.5 and 8.5 pounds per square inch."
Sorry for the long prologue. But wouldn't it be nice if labs were the same?
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Posted by Sten Westgard, MS
What's in a Sigma-metric of 3, 6, or even 11?
Sigma-metrics provide a useful way of classifying method performance and relating that performance to the QC that is necessary to “verify the attainment of the intended quality of test results,” which is a requirement of ISO 15189. But, Sigma-metrics are not foolproof. Does that bother you?
Maybe it's better if we frame this by referencing the 1984 cult film, This is Spinal Tap.
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Posted by Sten Westgard, MS
Alan Greenspan gave some instantly notorious testimony to the US Congress recently:
“I was right 70 percent of the time, but I was wrong 30 percent of the time,”
I'm not sure what was more concerning; the fact that he admitted that almost a third of the time he was wrong, or that he clearly believes that being right only 70% of the time was acceptable. Clearly, for a man once called "The Oracle" and Maestro, he was lowering the bar on the standards for judging him.
Testimony like that raises some instant questions:
- If Alan Greenspan was responsible for setting the direction of the world's greatest economy, is a 30% error rate acceptable?
- If Alan Greenspan was an airline, would you fly him?
- If Alan Greenspan was a core laboratory test, would you buy the instrument?
- If Alan Greenspan was a glucose meter, would you buy the device?
Posted by Sten Westgard, MS
We've probably never met before.
Maybe you're a reader of this blog. Or a visitor to the website, like the tens of thousands of laboratory professionals who visit the website every month, accessing hundreds of free articles, lessons, and examples of quality control. Or perhaps you're one of the thousands who have taken our online courses or purchased and read our many books and reference manuals.
But it is highly probable that we have never talked, emailed, or had a discussion with each other.
And maybe that's not good.
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Posted by Sten Westgard, MS