viewpointsV
DOI: 10.1145/2184319.2184329
the Business of software
a Measure of Control
YoU Can’t Control what you can’t measure.” So says Tom DeMarco at the beginning of his seminal book Controlling Software Projects.
3 DeMarco
was echoing Lord Kelvin who, a century
or so earlier, had said “If you cannot
measure it, you cannot improve it.”
These statements seem rather intui-
tive, and both quotes have been used
over the years to justify the develop-
ment and application of metrics pro-
grams in the business of software. Cer-
tainly it would be difficult to determine
if you have actually improved some-
thing if there were no way to quantify
the change—but there are other con-
siderations in measurement.
Watts, on first
In the mid-1990s I attended a presentation by the late Watts Humphrey
given to an audience of telecommunications executives where he gently
chided them for investing so heavily
in a measurement program that was,
to his mind, rather ineffectual. Humphrey’s point was that this particular company was, at the time, an SEI
CMM Level 1 organization. Such an
organization was characterized by the
Software Engineering Institute’s Capability Maturity Model as Initial or
should the control
chicken come before
the measurement egg
or should it be the
other way around?
“ad hoc” meaning the processes used
to build systems were recreated each
time for each system and each project. In Humphrey’s view this meant
that, to some extent, this company’s
development process was out of control; or perhaps more appropriately,
nothing could be inferred from measurement on this project since the
next project would likely use a quite
different process. As Humphrey put
it, the only thing measurement would
truly show was that the process was
out of control and they already knew
that. Therefore, he reasoned, the
company should invest first in stabilizing their processes before they
expended much effort in developing
measurement programs.
This message received a cold response. The executives and the company had already invested heavily in
their metrics program and they were
proud of it. They believed it was instrumental in their technological success
irrespective of their SEI level. So who
was right? Should the control chicken
come before the measurement egg or
should it be the other way around?
hawthorne Would
In purely metric terms, Humphrey
had a point—if the engine in your
car keeps surging uncontrollably it
is more important to fix it than to install a new speedometer. However,
this company had a long track record
of using measurements to generate
change. They intentionally employed
a form of Hawthorne Effecta; measurement was sometimes intended to
catalyze improvement rather than to
measure. At one point this company
instituted a large metrics program
that collected data from regular feed-
a Named after a study done at Western Electric’s
plant in Cicero, Illinois between 1924 and
1932 where significant productivity increases
were measured after apparently minor or placebo changes in the workplace environment.
The reasoning was that simply measuring
work activities tends to improve them.