Path: utzoo!utgpu!water!watmath!clyde!rutgers!husc6!necntc!dandelion!ulowell!apollo!marc
From: marc@apollo.uucp (Marc Gibian)
Newsgroups: comp.software-eng
Subject: Re: program complexity metrics
Summary: current complexity metrics do NOT improve code
Message-ID: <392487e8.fed5@apollo.uucp>
Date: 18 Dec 87 18:05:00 GMT
References: <561@ndsuvax.UUCP> <3850002@wdl1.UUCP> <242@pedsga.UUCP>
Reply-To: marc@apollo.UUCP (Marc Gibian)
Organization: Apollo Computer, Chelmsford, MA
Lines: 31

The current crop of complexity measures do NOT improve the code.  There
is an excellent article in a past ACM Communications on this issue.  The
conclusions of the acticle match the experiences of a major software
organization in Raytheon.  I will take the liberty here to summarize
the ACM article since I forget the issue number.  The basic conclusion of
the article is that no complexity measure currently exists that has been
designed specifically for the purpose for which it is being used by
software developers.  Secondly, current complexity measures do not
validate when tested against these software development goals.

The application of complexity measures at Raytheon, required by almost
every software contract there, is usually accomplished by requiring that
every module (however a module is defined) has a set of complexity values
less than some arbitrary number.  Unfortunately, the process of reducing
the measured complexity of a module most often decreased the quality of
the module, made it harder to maintain, harder to understand, and generally 
did not accomplish the intended goal.  I can provide specific examples if
anyone is interested.

I believe that a measure designed specifically to accomplish software
development goals, and validated against those goals, could be quite
helpful.  In the meantime, I think it is very dangerous to use the
current instruments since they mislead management and customers into
believing they have a good means of measuring some aspects of their
software.

Marc S. Gibian
Software Engineer
Apollo Computer

email:  marc@apollo.UUCP