
70 ◾ Software Metrics
this book where measurement is far from ideal but still paints a useful
picture of what is going on in the project.
2.4.3 Measurement in Extended Number Systems
In many situations we cannot measure an attribute directly. Instead, we must
derive a measure in terms of the more easily understood sub-attributes. For
example, suppose that we wish to assess the quality of the dierent types of
transport available for traveling from our home to another city. We may not
know how to measure quality directly, but we know that quality involves at
least two signicant sub-attributes, journey time and cost per mile. Hence,
we accumu ...