Precision

Definition

The correctness quality subfactor, precision, is the dispersion of the defects of quantitative data.

Measurement

Precision is typically measured in terms of:

• The variability, standard deviation, or confidence interval of quantitative data from its average value.

Requirements

See precision requirements.

Mechanisms

Typical mechanisms for increasing precision include:

• TBD

Guidelines

The following guidelines have been found to be useful when producing precision requirements:

• Numerical data can be accurate without being precise, and precise without being accurate.
• Precision is typically measures in terms of
• For example, a temperature sensor is precise to .1 degree Celsius, but not very accurate because it consistently under measures the temperature by 3.5 degrees. Thus, the standard deviation of the temperature measurements may be sufficiently precise, but nevertheless useless because the average temperature measurement returned by the temperature sensor is 3.5 degrees less than the true temperature making the temperature sensor not adequately accurate.