Viable within Constraints?

Each requirement is tested for viability within the constraints. This means you must consider each of the constraints, and ask whether the requirement contradicts it in any way.

For example, the users of the product can be considered a constraint. Whatever product you are specifying must be consistent with those users. The product must be easy for the user to operate , but sophisticated enough to provide the needed functionality. As an example, the following requirement for the IceBreaker product is not viable:

Truck drivers do not have the necessary information at hand to predict the time a road will freeze. They do not know which roads have been treated and which are in a dangerous condition. Coordinating a number of trucks treating multiple roads stretching over the whole of a county is a matter for centralized control.

You might also consider whether the organization is mature enough to cope with a requirement.

Do you have the technological skills to build the requirement? It is an easy matter to write a requirement, but it is sometimes a different, more difficult thing to construct a working solution for it. During the requirements activity there is little point in specifying a product that is beyond your development capabilities. This test is a matter of assessingunfortunately there can be no measurement herewhether the requirement is unachievable given the technical capabilities of the construction team.

Do you have the technological skills to build the requirement?

Do you have the time and the money to build the requirement? This test means estimating the cost of meeting the requirement, and assessing it as a share of the total budget. (The budgets should be listed as a constraint in section 4 of the requirements specification.) If the cost of constructing a requirement exceeds its budget, then the customer value attached to the requirement indicates how you should proceed: High-value requirements are negotiated, while low-value requirements are discarded.

Do you have the time and the money to build the requirement?

Is the requirement acceptable to all stakeholders?