Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!elroy.jpl.nasa.gov!decwrl!ads.com!saturn!jgautier From: jgautier@vangogh.ads.com (Jorge Gautier) Newsgroups: comp.software-eng Subject: Re: use of metrics Message-ID: Date: 18 Jun 91 21:01:08 GMT Sender: usenet@ads.com (USENET News) Organization: Advanced Decision Systems, Mountain View, CA 94043, +1 (415) 960-7300 Lines: 42 In-Reply-To: dc@sci.UUCP's message of 17 Jun 91 13:03:40 GMT In article <1205@mgt3.sci.UUCP> dc@sci.UUCP (D. C. Sessions) writes: > At a large and *very* well-regarded institution, the metrics program > had determined that successful projects devoted A % of applied time > to initial specification, B % to initial design, C % to coding, D % > to debugging, etc. Having determined this, individuals were > expected to conform to the profile. One misfit, for whatever > reason, spent more time on the initial phases and (perhaps as a > result) converged more rapidly on working product. (Maybe the > relatively short test programs had something to do with the fact > that his products used DFT principles, or perhaps with the fact that > he spent more time on the test plan -- who knows?) > > As with any nonconformist, his misguided notions eventually resulted > in his downfall. When evaluation time came around, he was upbraided > for insufficient attention to debug & test. The word got around, > and other developers who had been thinking of trying to match his > consistent on-time low bugcounts rapidly disabused themselves of the > notion. As I have noted previously in this group, metrics and correlations do not fully support decision making in software development. Inductive reasoning is not truth preserving, it merely points out possible truths. You need some kind of deduction to justify conclusions suggested by induction. For example, simple association of success or failure with measurements is not enough. At some point you need to find the real cause of the success or failure. This is of course much more difficult than measurement and correlation, so it is rarely done, and we all pay the price. Some people are blinded and falsely reassured by metrics. They read a few articles and books and they think that metrics is the answer to everything in software development. They come up with a few correlations and all of a sudden they think they know what's good and bad in software development. They ignore significant but un-metricized phenomena in favor of measurable but insignificant ones. And (unfortunately) sometimes they make decisions about software development and software developers. Sad but true. -- Jorge A. Gautier| "The enemy is at the gate. And the enemy is the human mind jgautier@ads.com| itself--or lack of it--on this planet." -General Boy DISCLAIMER: All statements in this message are false. "Mommy, where do programs come from?"