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Love is a many-splendored thing

One problem you will have encountered in trying to clarify or to quantify, objectives, is that there might be no one single satisfactory dimension describing it.

Let’s say you quantify one value, like ‘Love’, and feel something is missing, so you try again. But then something else is missing. You might wrongly conclude that this value can not be quantified in a satisfactory way.

But you cannot conclude, from your failure to find one single quantification scale of Love, or any other value, that there are no quantification scales.

The correct answer is very likely to be that there is a satisfactory ‘set’ of Quantification Scales, which together best describe the objective, be it ‘Love’ or ‘Usability’.

When you find several potential ways to quantify an objective. Which one is the right one? It is tempting to ask.
‘All of them and more’ might be the right answer!

An old electrical handbook recommended dividing up concepts ‘until quantification became obvious’.




Rene Descartes (1596-1650) recommended the same approach (‘Discourses on the Methods’).

or as we would say it, inspired by Rene
"Some objectives are ‘compound’, they have multiple dimensions, each with a different nature.
 So a good way to manage them 
is to have multiple scales defining them." - Tom Gilb


Case: IBM Usability

Once, the CEO at IBM decided that Usability was the ‘wave of the future’, for the new Personal Computers, and Tom was asked to help out by IBM.

I (Tom) had suggested to IBM that if they wanted to do better usability on their IBM PC, and the CEO had asked for exactly that, then they had to quantify ‘usability’ in order to manage it. The problem was, although IBM agreed with me in principle, none of us, or anyone we knew, had ever quantified ‘usability’ for a PC - or anything similar.

I worked with Max Wilson and John Bennett of IBM in San Jose California. But it took months before we realized that the useful answer was ‘many dimensions’, not one.
We tried one ‘obvious’ usability idea after another, but they did not work. There was always some other usability consideration they did not contain.

One day Max walked into our meeting room and said “Eureka”. “The solution is not a single quantification scale, it is a set of them”.

“Of course”, I thought to myself, “that is exactly what I learned in my University Philosophy course from Descartes!” I felt silly I had not seen this before.

The many-dimensional Usability model was adopted by IBM substantially, and in the long term, as their way of treating usability questions.


Figure A. Some compound quality attributes. Including the one we worked out at IBM in the case above. (Source Competitive Engineering Book, Figure 5.3, this book contains details of Usability Scales, many other interesting quality scales of measure, and of 7 more usability sub-attributes). We have now made Competitive Engineering a free digital download.

Rene Descartes. Quotation

“To accept nothing as true which is not clearly recognized to be so: that is to say, carefully to avoid precipitation and prejudice in judgments, and to accept in them nothing more than what was presented to my mind so clearly and distinctly that I could have no occasion to doubt it.
To divide up each of the difficulties which I examined into as many parts as possible, and as seemed requisite in order that it might be resolved in the best manner possible.
To carry on my reflections in due order, commencing with objects that were the most simple and easy to understand, in order to rise little by little, or by degrees, to knowledge of the most complex, assuming an order, even if a fictitious one, among those which do not follow a natural sequence relatively to one another.
In all cases to make enumerations so completely and reviews so general that I should be certain of having omitted nothing. “

Practical Tip

• Assume that each of your top-level objectives is compound (a set of Scales define each objective). Assume they are not elementary (one Scale defines one objective) until proven otherwise.
• Make a list of possible sub-attributes. Brainstorm a list with colleagues. Find a list on the internet. Search for ‘Usability metrics’ or similar texts.

Policy Suggestion: Decompose Compound Objectives.

When a top-level objective is best described with more than one quantification scale, it should be decomposed into its’ elementary quantified components.

Case: The many-splendored attributes of Rock solid Robustness


Rock Solid Robustness:

Type: Complex Product Value Requirement.
Includes: 
{Software Downtime, 
Restore Speed,
 Testability,
 Fault Prevention Capability,
 Fault Isolation Capability,
 Fault Analysis Capability, 
Hardware Debugging Capability}

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