Sigma Performance Levels – One to Six Sigma

When learning about Six Sigma, it may help to consider these charts, which detail how sigma level relates to defects per million opportunities (DPMO), and some real-world examples.

Sigma Performance Table

Sigma Performance Levels – One to Six Sigma

Sigma Level
Defects (or Errors) Per Million Opportunities (DPMO)
Yield (or Produced or Delivered) Correctly (%)

1
691,462
30.85

2
308,538
69.146

3
66,807
93.319

4
6,210
99.379

5
233
99.9767

6
3.4
99.9997

What Would Sigma Values Look Like In The Real World?

It’s one thing to see the numbers and it’s a whole other thing to see how it would apply to your daily life.

Real-world Performance Levels

Situation or Example
In 1 Sigma World
In 3 Sigma World
In 6 Sigma World

Pieces of your mail lost per year [assuming 1,600 opportunities per year]
1,106
107
Less than 1

Number of aircraft takeoff or landing incidents [assuming one takeoff and landing per flight, round trip]
25 times per 10 flights
24 times per 100 flights
12 times per million flights

Number of empty coffee pots at work (who didn’t fill the coffee pot again?) [assuming 680 opportunities per year]
470
45
Less than 1

Number of telephone disconnections [assuming 7,000 talk minutes]
4,839
467
0.02

Erroneous business orders [assuming 250,000 opportunities per year]
172,924
16,694
0.9

Electricity outage [assuming 30 day month = 720 hours]
500 hours
45 hours
9 minutes

In the United States alone if the sigma level were between 3 and 4, there would be 50 newborn babies dropped per day and 5,000 incorrect surgical procedures per week.

Not all opportunities and defects are created equal. I think all flight passengers would agree that a flight delay is less worrisome than a flight incident on landing.