About this lesson
Businesses rely on data and data relies on accurate measurements to be meaningful. The data measurement is made of two components, the value of the true item and the variation due to the measurement system.
When to use
Data measurement is used to measure an item and draw conclusions about that item. It is used to measure a process and draw conclusions about the process. And it is used to measure a portion of an item or process, or to draw inferences about the rest of the item or process.
Data measurement is everywhere in business today. Virtually everything is measured, and a data item is created to convey the value of the item or process that is measured. Businesses use data to make both strategic and tactical decisions. More and more business people are questioning the accuracy and reliability of the data they receive.
Lean Six Sigma projects rely on data throughout the process. The data is used to both understand the problem and discover a solution. Again, reliable and accurate data is critical to making wise decisions in a Lean Six Sigma project.
Data measurement is a process. As a process it is always susceptible to variation. There is common cause variation from the measurement system. There may also be special cause variation from incorrectly using a measurement system.
The variation in the measurement system is graphically depicted below. The measured value is represented by the hypotenuse of a right triangle. One side of the right triangle represents the variation in the item being measured. The other side represents variation in the measurement system. This variation in the measurement system introduces an error that causes the measured value of the item to be different than the actual value. The magnitude of this measurement error must be known in order to determine if the measurement systems will provide accurate reliable data.
Hints & tips
There are many possible causes of measurement error which will be discussed in more detail in other lessons.
- A measurement system may be perfectly adequate for providing measurements in one application but inadequate in another.
- A thermometer for checking body temperature when you are sick will explode if you try to use in in the oven for checking on items being baked.
- Likewise, a baking thermometer does not have the discrimination to be used effectively to check your body temperature when you are sick.
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