Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!weyrich!orville From: orville@weyrich.UUCP (Orville R. Weyrich) Newsgroups: comp.software-eng Subject: Re: Metrics Example Message-ID: <1991May25.085941.3526@weyrich.UUCP> Date: 25 May 91 08:59:41 GMT References: <1991May23.231339.22418@netcom.COM> <1991May24.201741.14138@netcom.COM> Reply-To: orville@weyrich.UUCP (Orville R. Weyrich) Organization: Weyrich Computer Consulting Lines: 80 In article <1991May24.201741.14138@netcom.COM> jls@netcom.COM (Jim Showalter) writes: >>The point that worries me is this assertion that the metrics are ``real >>measures''. [I'm happy to believe that they are; it's just that I think they >>need justification. As earlier posts of mine have said, just because they're >>*numbers* doesn't make them *meaningful*.] > >We are veering off into semantics and the philosophy of causality. Define >what you mean by "meaningful". In a previous post I pointed out that if >rutabaga consumption per developer could be shown to be a good predictor >of project success, then it was a valid metric with which to make such >predictions. The counterargument is absurd: "Yeah, there's a 100% correlation, >but we won't use that metric anyway because it's SILLY.". >If they can be shown to have a correlation with project success, then, yes, >they ARE real measures. What else would you call them? Yes, if there is a demonstrated correlation, then they can be used as a predictor of success. The danger is that the conclusion might be drawn that if the project seems to slipping, the management should take steps to increase the rutabega consumption. This would only be valid if there were a demonstration of cause and effect. Observation of a cause/effect relationship implies a correlation; the observation of a correlation does not necessarily imply a cause/effect relationship. >We think they're real because project in trouble tend not to have any >metrics, and projects on schedule tend to use metrics. As for WHY we >think they work, this is just the causality issue again--I'm personally >not particularly concerned with why the metrics work: I'm concerned >with them working, and that's about it. Just to be the devil's advocate, can we assume that: 1) Projects in which the managers feel that their subordiantes are not too bright, but are doing the best that they can, and cannot be induced to improve, may be in trouble. 2) Projects with such managers do not use metrics, because they feel that it is no use -- you can't induce the programers to improve. In this situation, it seems to me that the project will be in trouble, and will not be using metrics. Inducing the manager to use metrics will not solve the problem. Inducing the manager to change his/her attitude will. >Let me make my position clear: I'd practice VOODOO if someone could >provide me with evidence that projects using it are more successful >than projects not using it. And I would do this without spending >ten seconds trying to figure out WHY it worked. Be careful here -- it may be that programmers who enjoy rutabegas come from a part of the world where VOODOO is prevalent, and that rutabegas contain some particular nutrient which stimulates programmers to do a particularly good job. If you simply introduce VOODOO into your failing project, you are not likely to get the desired effect, and will have wasted time and effort that would have been better spent encouraging your project team to eat more rutabegas. This is why the FDA is so down on "quack" medicines. I would insist on evidence that using VOODOO *causes* projects to be more successful before committing to using VOODOO [unless you have a boss yelling "I don't care what you do, just do SOMETHING so that I can tell the Board of Directors that the problem has been taken care of." :-)]. I agree that it is not so important to determine how the cause induces the effect. But even, here, it is useful to ponder. If VOODOO is demonstrated to cause better projects, do you need to have the whole shebang, or is it sufficient to toss a dead chicken at the programmers periodically? It certainly is cheaper to pick up a few dead chickens from beside the road than it is to import a witch-doctor [you think that MD's are overpaid? You should check out what even a mediocre witch-doctor gets paid! :-)]. -------------------------------------- ****************************** Orville R. Weyrich, Jr., Ph.D. Certified Systems Professional Internet: orville%weyrich@uunet.uu.net Weyrich Computer Consulting Voice: (602) 391-0821 POB 5782, Scottsdale, AZ 85261 Fax: (602) 391-0023 (Yes! I'm available) -------------------------------------- ******************************