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I am obviously not expressing myself very well today.  My use of the word
"develop" was in reference only to design and code.  I agree fully that the
total -cost-, on average, will be lower for the Ada project.  The argument
is completely with the -risk of cost growth-.  So, for example, if I were
to estimate the cost of a project in C, I might come up with \$1M, where, if
I were to estimate the cost of the same project in Ada, I would likely come
up with something less (let's say \$750K).  However, for the C case, my risk
of cost increase is very low, because there are many ways to use metrics to
estimate the number of errors that will be put in during coding.  With the
Ada estimate, the risk of cost increase is higher, due to the extra cost
associated with the design work associated with a well-designed Ada
program.  This cost is related to higher-level design problems.

For example, to get to a detailed design review, let's say 65% of the work
is done in the Ada case, but only 20% in the C case.  So the C project has
spent \$200,000, where the Ada project has spent \$487,500.  In the simplest
case, where a design flaw is found requiring starting completely over, the
C project will end up \$200K over (or 20%), costing a total of \$1.20M and
the Ada project will be \$487,500 over (or 65%), costing a total of \$1.2375M.

If you scale the numbers up a couple of orders of magnitude, a cost overrun
of 65% will likely get a congressional investigation, where a cost overrun
of 20% might get a slap on the wrist.

One can argue with my numbers (please do; I unfortunately do not have the
metrics available to give accurate comparisons), but it does not help to
say something is "patently false".  Not many people will be persuaded with
that.

Roger

At 03:43 PM 6/9/1999 , Carlisle, Martin wrote:
>This strikes me as patently false, along with your statement that C
>obviously costs less to develop than Ada.  I would say in my experience, C
>costs less up to a couple hundred lines of code.  Beyond this, I have found
>myself far more productive in Ada than I ever was/would have been in C.
>
>I suppose it is probable that I had executables far sooner in C, but I
>certainly have *working* ones far sooner in Ada.
>
>--Martin
>
>-----Original Message-----