
350 ◾ Software Metrics
and two open sources systems. e studied systems included from 4 to 7
unique design pattern types, with a range of 6–35 pattern realizations—
actual implementations of a pattern, as one pattern can be “realized” sev-
eral times in a design. Here, the number of design pattern realizations
served as a measure of design size. e studies found that the classes that
played roles in design patterns were more, not less, change prone than the
classes that were not part of a pattern.
If we are interested in run time properties of a design, we can measure the
size of a running system in terms of the number of active objects over ...