1 number of statements (N_STMTS): counts the average number of executable statements per component [1–50].
2 cyclomatic complexity (VG): as defined by McCabe (1976). It is a metric based on graph theory that represents the number of linearly independent paths in a connected graph, in our case, the component control flow graph. It is considered an indicator of the effort needed to understand and test the component [1–15].
3 maximum levels (MAX_LVLS): measures the maximum number of nestings in the control structure of a component. Excessive nesting reduces readability and testability of a component [1–5].
4 number of paths (N_PATHS): counts the mean number of non-cyclic paths per component. It is another indicator of the number of tests necessary to test a component [1– 80].