Cocomo2 adaptation & reuse factors

[Phil Pulley]

I am looking for some clarification on the correct use of the ‘IM'
factor when dealing with adaptation & reuse in the COCOMO2 model.

Am I right in assuming that this factor relates to the integration
effort required for the creation of the adapted component only and not
the effort required to integrate this adapted component into the
overall product?

I find the description of this in the Cocomo2 book and online help a
little confusing – but perhaps I'm just being thick! :-)

Any help appreciated.


Phil

[Dan Ligett]

"Phil Pulley" <pulley_p@hotmail.com> wrote in message
news:7041fc41.0402190123.27cfe723@posting.google.com... I am looking for some clarification on the correct use of the 'IM' factor when dealing with adaptation & reuse in the COCOMO2 model. Am I right in assuming that this factor relates to the integration effort required for the creation of the adapted component only and not the effort required to integrate this adapted component into the overall product? I find the description of this in the Cocomo2 book and online help a little confusing - but perhaps I'm just being thick! :-)

Phil, yeah, this is a little fuzzy....

But "Software Cost Estimation with COCOMO II" (Boehm, et al) says that IM
"is the percentage of effort required to integrate the adapted software into
an overall product...".

I tell our customers that even if DM=0 and CM=0 in an adaptation project, it
may make sense to set IM=100. Just because you get the code for free (i.e.
it's reused) doesn't mean that it won't break your system. You still have
to test.

Also keep in mind that DM, CM, and, IM can be greater than 100% (as noted in
"Software Engineering Economics"). It may cost you more to reuse some code
than to start from scratch.

Dan Ligett, Softstar Systems, (603) 672-0987, http://www.SoftstarSystems.com