[comp.software-eng] measuring software complexity

cml@tove.cs.umd.edu (Christopher Lott) (04/17/91)

In article <36650004@hpopd.pwd.hp.com> daves@hpopd.pwd.hp.com (Dave Straker) writes:
>On measuring complexity...
>
>Before you measure anything, you should ask: Why am I doing this?
>What am I going to do with the information? What questions will
>it help answer? What decisions will it help me make?

u
This seems to be a good spot to put in a plug for the Goal/Question/Metric
paradigm, developed by Dr. Victor Basili and others here at U Maryland.
When doing measurement, our group has found that the bottom-up approach
leads to FAILURE.  (lessee, here's a metric that's cheap to compute, let's
see what it tells us, yeah, that's it.)

A vastly better approach is to start from the top.  First you state your
Goals.  These may be to characterize, to evaluate, etc.  Then you write
some Questions that will allow you to achieve your goals.  E.g., what was
the cost of X, how many Y were found in phase Z.  Finally, you define and
look for Metrics that will answer your Questions.  Questions may apply to
different Goals, and similarly Metrics may participate in answering different
Questions.

This is a specialization of the scientific method.  State problem, write
hypothesis, experiment, evaluate, repeat.  For more information, email me
and I'll dig more to find tech reports which I can send out; they're free,
but we're suffering from a NASTY budget crunch, so a preaddressed mailer
or some such would be Most Helpful.  For even more information, have your
organization send you for a 6-month or longer sojourn here at Maryland CS.

chris...
--
Christopher Lott \/ Dept of Comp Sci, Univ of Maryland, College Park, MD 20742
  cml@cs.umd.edu /\ 4122 AV Williams Bldg  301 405-2721 <standard disclaimers>

daves@hpopd.pwd.hp.com (Dave Straker) (04/19/91)

> This seems to be a good spot to put in a plug for the Goal/Question/Metric
> paradigm, developed by Dr. Victor Basili and others here at U Maryland.

I support this plug. I came across the notion last summer, and it has
changed my life! It's one of those things that is so obvious that you
wonder why you didn't use it before.

It is probably the driver for my previous response (I've internalised
it, so I can't tell any more).

This approach also fits neatly into the Hoshin planning used widely here
at HP. This (approximately) goes 'goal/tactic/metric'. The 'question' helps
determine the tactic (what must I do to answer the question?).

Dave Straker            Pinewood Information Systems Division (PWD not PISD)
[8-{)                   HPDESK: David Straker/HP1600/01
                        Unix:   daves@hpopd.pwd.hp.com

cml@tove.cs.umd.edu (Christopher Lott) (04/21/91)

In <some article> I write:
>> This seems to be a good spot to put in a plug for the Goal/Question/Metric
>> paradigm, developed by Dr. Victor Basili and others here at U Maryland.

In article <36650006@hpopd.pwd.hp.com> daves@hpopd.pwd.hp.com (Dave Straker) writes:
>I support this plug. I came across the notion last summer, and it has
>changed my life! It's one of those things that is so obvious that you
>wonder why you didn't use it before.

High praise indeed!  Well, I don't know about the life-changing possibilities
of this approach, but here's the reference I promised:

Basili, Victor R., and H. Dieter Rombach,
"The Tame Project:  Towards Improvement-Oriented Software Environments,"
IEEE Transactions on Software Engineering,
Vol. 14, No. 6, June 1988, pp. 758-773.


Reprints available from me by sending a preaddressed envelope with enough
postage for about 10 8.5x11" sheets to my address below.

chris...
--
Christopher Lott \/ Dept of Comp Sci, Univ of Maryland, College Park, MD 20742
  cml@cs.umd.edu /\ 4122 AV Williams Bldg  301 405-2721 <standard disclaimers>