
80 Empirical Research in Software Engineering
Chidamber and Kemerer (1994) dened coupling as:
Two classes are coupled when methods declared in one class use methods or instance
variables of the other classes.
This denition also includes coupling based on inheritance. Chidamber and Kemerer
(1994) dened coupling between objects (CBO) as “the count of number of other classes
to which a class is coupled.” The CBO denition given in 1994includes inheritance-based
coupling. For example, consider Figure 3.5, three variables of other classes (class B, class C,
and class D) are used in class A, hence, the value of CBO for class A is 3. Similarly, cla ...