alternative2: how well the system does its Product-Functions as experienced by Stakeholders.
alternative3: how well the Product-Function performs as experienced by Stakeholders.
Illustration: interactions are everything. We would not even know of an apple, had it not been for the interactions between the apple and us. We see, feel, taste and smell it etc. These interactions between the apple and us, I call interacting Qualities or Product-Values. The Qualities of an apple (or any Product) are what make us appreciate it. It might look-, smell-, feel-, great or less so. It will be healthy or less so. It will store well or rot fast.
We choose to buy and eat one food (or any Product), rather than another, based on the Product-Values that we want. To develop or buy an apple we must understand its Product-Values, the same holds true if we want to successfully develop any Product or Service.
Some Product-Values (Qualities) of a car: Cost, comfort, acceleration, braking ability, its precision in steering, fuel mileage, style and beauty, its maintenance costs, road handling, ease of opening the hood, intuitiveness of the air-conditioner, intuitiveness of adjusting the seats, space, environmental pollution, quietness, etc., as well as customer satisfaction, friendly sales staff, image etc. are all examples of what I call Product-Values that we might evaluate when buying a car.
Scale: average time in minutes, to install, the system.
Meter: have 3 people install the system, time them, and average the time.
Past  120 min.
Goal  30 min.
1. A Product-Value is a System performance Attribute. All Systems have a large number of Product-Value Attributes in practice. In a given situation, only the relevant Product-Value Attributes will be specified: these are the Product-Values specifically valued by the Stakeholders.
2. All Product-Values can be described numerically, using a defined Scale, or set of Scales. Existing Product-Value Levels can be specified as Benchmarks, and needed future Product-Value Levels, can be specified as targets and Constraints.
4. Product-Value is characterized by these traits:
• Product-Value describes ‘how well’ a Function is done
• Product-Value is valued to some degree by some Stakeholders of the System
• More Product-Value is generally valued by Stakeholders; especially if the increase is free, or at lower Cost, than the value of the increase
• Product-Value Attributes can be articulated independently of the specific Means (designs) used for reaching a specific Product-Value Level – even though all Product-Value Levels depend on the particular designs used to achieve them
• A specific Product-Value can be a described in terms of a Complex Concept, consisting of multiple Complex and/or Elementary Product-Value Concepts
• Product-Value is variable (along a definable Quantification-Scale: as are all Scalar Attributes)
• Product-Value Levels are capable of being specified quantitatively (as are all Scalar Attributes)
• Product-Value Levels can be measured in practice
• Product-Value Levels can be traded off to some degree; with other System Attributes valued more by Stakeholders
• Product-Value can never be perfect (100%), in the real world
• There are some Levels of a specific Product-Value that may be outside the state of the art at a defined time and under defined circumstances
• When Product-Value Levels increase towards perfection, the Resources needed to support those Levels tend towards infinity