Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!dali.cs.montana.edu!uakari.primate.wisc.edu!aplcen!aplcomm!uunet!mcsun!ukc!tcdcs!swift.cs.tcd.ie!omahony From: omahony@swift.cs.tcd.ie Newsgroups: comp.software-eng Subject: Re: COCOMO Message-ID: <1991Jun17.152717.7965@swift.cs.tcd.ie> Date: 17 Jun 91 15:27:17 GMT References: Distribution: comp Organization: Computer Science Department, Trinity College Dublin Lines: 33 In article , ahl@technix.oz.au (Tony Landells) writes: > I'm looking for opinions of COCOMO. I was on a course about software > quality assurance and they mentioned it as a methodology which > produces a lot of useful figures, but the comments were accompnied by > the disclaimer "I haven't used it, but people that do seem to think > it's pretty good". > The COCOMO model is based on working backwards from measurements taken on a variety of projects (in ASM, FORTRAN etc) carried out many years ago, to get some formulae that can then be used to work forwards. In "Software Engineering Economics", Boehm did some tests of it's accuracy when working forwards and claimed that it is "accurate to within a factor of 2 60% of the time". Based on experience within your organisation, it is possible to more accurately calibrate the formulae, and more precise estimates may be obtained after that. One of it's problems is that before the model can be used, the person doing the costing must make a (guess)timate! of how many lines of source code the finished software product will contain. Since the output is only as good as the input, the accuracy of the final result is again dependent on the experience of the person conjuring up this figure. Naturally, it is possible to fudge this figure to yield what Boehm et al call the "Cost to Win!" Still, it has to be better than picking ALL the figures off the top of your head! Donal O'Mahony Computer Science Dept Trinity College Dublin, Ireland