"Metrics are a system of parameters or ways of quantitative and
periodic assessment of a process that is to be measured, along with the
procedures to carry out such measurement and the procedures for the
interpretation of the assessment in the light of previous or comparable
assessments. Metrics are usually specialized by the subject area, in which case
they are valid only within a certain domain and cannot be directly benchmarked
or interpreted outside it."
Metrics are measurements. It is as simple as that. We use them all the time
in our everyday lives. Entangling them in wordy definitions is just intended to
make them seem more mysterious and technical than they really are.
So what sorts of things do we measure in our daily lives and how do we use
them? Shopping for food is a good place to start. At the meat counter, there is
a choice of cuts of different kinds of meat, all at different prices. If we just
look at the total price, we may be misled. A nice round steak might cost $10.00
while a round roast might cost $8.00 even though it weighs the same as the
steak. So to get the best value for our money we tend to look at the price per
unit weight. This is a microcosm of the field of metrics.
There are two basis types of metrics. The first type is the elemental or
basic measurement such as weight, length, time, volume, and in this example,
cost. The second type is derived, normally from the elemental measurements. At
the meat counter, the derived metric is dollars/weight (VIZ. $7.49/kg). This is
called a normalized metric.
Generally speaking, normalized metrics are the most useful because they allow
us to make comparisons between things that are different. Some other examples
are miles/gallon, dollars/gallon, dollars/share, dollars/hr, and dollars/square
foot to give but a few.
We also see metrics in sports. In hockey its shots on goal and plus/minus
ratio. In baseball its batting average and errors per game. All of these numbers
are provided in newspapers and sports magazines and if they disappeared there
would be a great uproar among fans.
“When you can measure what you are speaking about and express it in numbers,
you know something about it; but when you cannot measure it, when you cannot
express it in numbers, your knowledge is of the meager and unsatisfactory kind.”
- Lord Kelvin
Now Lord Kelvin wasn't right about everything he spoke about. He predicted
that heavier than air flight was impossible. But about metrics, he was dead
We as shoppers apply this principle whenever we go to the market. If a cut of
meat is marked $10.00 but has no weight assigned, we are likely to look for
something else. The same would apply if the weight were given but no price. This
is just plain old ordinary common sense. Yet we may go though our professional
lives without using metrics to guide us in our work. Maintaining a "meager and
unsatisfactory" knowledge about the way you earn your living is probably not the