Quantification vs Measurement
“If you think you know something about a subject, try to put a number on it. If you can, then maybe you know something about the subject. If you cannot then perhaps you should admit to yourself that your knowledge is of a meager and unsatisfactory kind.”
~ Lord Kelvin, 1893
Some folks seem to mix up the idea of quantification with the idea of measurement.
“Why does it matter?” I suspect you might ask. I’ll leave you to be the arbiter of that.
I just wanted to flag that in my view (and in the dictionary), there’s a difference:
“A fundamental, generic term used when referring to the measurement (count, amount) of a scalar, vector, number of items or to some other way of denominating the value of a collection or group of items.”
“The act of assigning a quantity to (something).”
Tom Gilb defines quantification thusly:
“Quantification, even without subsequent measurement, is a useful aid to clear thinking (what is this about?) and good communication (this is the goal, gang).”
~ Tom Gilb
“To ascertain the quantity of a unit of material via calculated comparison with respect to a standard.”
In A Nutshell
In a nutshell, the two terms differ in that:
- Quantification is about a way to have more meaningful discussions, less obscured by subjective language, whilst
- Measurement is about seeing more objectively what’s happening in your world.
In general we can fairly quantify anything; measuring things is often more problematic.
If you have your own definitions which you prefer more, or any other feedback, I’d love to hear from you.
Principles of Software Engineering Management ~ Tom Gilb
Competitive Engineering ~ Tom Gilb
Software Metrics ~ Norman E. Fenton
Quantifying Stakeholder Values ~ Tom Gilb (pdf)
Making Metrics More Practical in Systems Engineering ~ Tom Gilb (pdf)