Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!sdd.hp.com!hplabs!otter.hpl.hp.com!hpltoad!cdollin!kers From: kers@hplb.hpl.hp.com (Chris Dollin) Newsgroups: comp.software-eng Subject: Re: Metrics Example Message-ID: Date: 23 May 91 08:14:44 GMT References: <24600@unix.SRI.COM> Sender: news@hplb.hpl.hp.com (Usenet News Administrator) Organization: Hewlett-Packard Laboratories, Bristol, UK. Lines: 84 In-Reply-To: hlavaty@CRVAX.Sri.Com's message of 22 May 91 15:26:50 GMT Nntp-Posting-Host: cdollin.hpl.hp.com hlavaty@CRVAX.Sri.Com says: ... Kers. Caravan: sorry if my original response to your post was "flamelike" - it was not intended to be. From your repsonse, I think you missed my point entirely. Mine was not the original post - you may have been misled by my comment about ``peculiar''. And I don't think I missed your point. As it stated, my response was not intended to criticise the use of *metrics* - it was to point out (what I regarded as) weak points in your *case*. Unless you can address these issues, you are vulnerable to attack from the anti-metrics brigade. Annecdotes are not good enough as evidence. ... (and yes, I have confused qualitative with subective. I welcome discussion on how they're different). Quantatative ~= with numbers. Qualitative ~= without numbers. Subjective ~= private, local, person-dependant. Objective ~= public, ``real''. [I'm *not* attempting to give a precise definition here, and I *know* subjective doesn't equate to unreal. I'm attempting to compare and contrast. ``I have a strength 5 headache'' is quantative and subjective. ``My briefcase is heavier than my mug'' is qualitative and objective. ``McKillip writes better fantasy than Anthony'' is qualitative and subjective [*1]. ``This window is 80 characters with in font hp8.6x13'' is quantitive and objective. I seized on metrics as the answer to my problems. If I could get the managers to show me various metric data, then *I* could interpret it my own way and make my opinions! But why should your opinions be any better than theirs? A big advantage gained using metrics is that it gave me a window into the development process through which I could look to determine if things were in control. With the metric charts, now my questions would be "Gee, you had a large error spike last month. What caused that?" or "You didn't get your normal amount of unit testing in last month. Why was that?" Suddenly we were discussing *real* issues. The only justification you have presented for the act of faith that a ``large error spike'' is a ``real'' issue is industrial studies data [omitted above]. Go for it! *That* is the thing that makes metrics important - *data exists that show that they work*. It's not because their ``quantative'' (but being ``objective'' helps). The answers to these questions invariably led to the identification of specific problems the manager was having (not enough computers, someone quit unexpectedly, and the occassional "that's a problem we don't know how to solve just yet"). Now I had what I needed - a window into the process that communicated to me enough information to ask the right questions. Great. Again, it's not the *numbers*, it's what they *mean*, and the existance of a communications process. After a while, the chief software manager at the company and the program manager started using these charts themselves for their own purposes. They realized that they couldn't afford to miss this information! And that is data worth having. I hope this illustrates my point more concretely. And I hope my remarks help you to present you case better when you get the next bunch of people to convince. Number's aren't real, they're complex - use with caution; don't place the numbers above their meaning. [*1] Some people don't believe the statement, some people don't think it's subjective, but I'd be surprised if anyone thought it was quantative. -- Regards, Kers. | "You're better off not dreaming of the things to come; Caravan: | Dreams are always ending far too soon."