Law of Demeter confirmed by experiment at University of Maryland

The article

@ARTICLE{basili:oo-metrics,
AUTHOR = "V. Basili and L. Briand and W.L. Melo",
TITLE = "A Validation of Object-Oriented Design Metrics as Quality Indicators",
JOURNAL = ieee-se , (IEEE Transactions on Software Engineering)
YEAR = 1996,
PAGES = "751-761",
MONTH = "October",
VOLUME = 22,
NUMBER = 10
}

tests the hypothesis H-RFC: Classes with larger response sets implement
more complex functionalities and are, therefore, more fault-prone.

RFC (Response For a Class) is the number of C++ functions directly invoked by
member functions or operators of a C++ class.

Following the Law of Demeter reduces RFC.

Basili et al. find:
RFC was shown to be very significant. The larger RFC, the larger the
probability of faults in the software.

This empirical investigation indicates that it is useful to
follow the Law of Demeter to reduce bugs in the programs.