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From: coggins@coggins.cs.unc.edu (Dr. James Coggins)
Newsgroups: comp.software-eng
Subject: Re: Using COCOMO to estimate development schedules
Keywords: COCOMO, software development
Message-ID: <7634@thorin.cs.unc.edu>
Date: 6 Apr 89 16:02:21 GMT
References: <351@tahoma.UUCP> <4148@ttidca.TTI.COM> <7518@thorin.cs.unc.edu> <4183@ttidca.TTI.COM>
Sender: news@thorin.cs.unc.edu
Reply-To: coggins@cs.unc.edu (Dr. James Coggins)
Organization: University Of North Carolina, Chapel Hill
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In article <4183@ttidca.TTI.COM> hollombe@ttidcb.tti.com (The Polymath) writes:
>
>Apparently I didn't make myself clear.  My (former) boss didn't compare
>COCOMO figures to seat-of-the-pants estimates.  He plugged actual figures
>from real, completed projects into the COCOMO formulas and compared the
>COCOMO projections with the actual project figures.
>
>He found the COCOMO projections to be wrong by as much as 50%.
>
>Maybe your company can live with 50% cost overruns or project over-bids.
>Ours couldn't.
>
This just shows how little you know about estimation.  A factor of 2
is not bad for an initial estimate such as one obtains from the Basic
level of COCOMO.  Is this what you plugged numbers into?  I assume so,
since your description of the process your boss went through is
superficial.  The deeper levels of COCOMO (called Intermediate and
Detailed COCOMO) have plenty of degrees of freedom to bring that
estimate right into line with practice.

Read the book; note the assumptions; study the results; test the results.
Then complain.

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Dr. James M. Coggins          coggins@cs.unc.edu
Computer Science Department   
UNC-Chapel Hill               Complaining is not a spectator sport.
Chapel Hill, NC 27599-3175    
and NASA Center of Excellence in Space Data and Information Science
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