What are Requirements?
How will we know if the streetlight replacement project has succeeded? Simple replacement of the streetlights is certainly not enough: focusing just on statements made by different members of the governing body over the last several months there is an expectation of certain energy savings over time. And also an expectation of certain maintenance costs savings over time. And, an expectation of street safety. And, an expectation that the project will place the city on a path toward Dark Sky Community designation. And, an expectation that the project will protect the city’s special ambience. And, …
Project success means meeting the agreed upon expectations of all the project stakeholders. Project Requirements are nothing more than the clear and unambiguous statement of stakeholder expectations: the agreed-upon definition of project success. The only way this is possible is if these expectations are all clearly understood by all the project’s stakeholders – mayor, councilors, and community members – at the project’s outset.
Project requirements are a question of policy. They are an expression of the Governing Body’s priorities. They are the reason that the project is funded. It is quite simply impossible for project requirements to exist and not be known to and approved by the Governing Body. If the Governing Body does not know whether project requirements exist, then we can say definitively that project requirements do not exist.
What are Specifications?
Project requirements define the “problem” the project exists to “solve.” Specifications are the technical constraints imposed by the requirements on the solution. For example, if street lighting project success means a certain energy savings, then the acceptable luminaires must – averaged across the entire project – have a certain minimum efficiency. And, if the project success requires a certain savings in maintenance costs, the acceptable luminaires must have a certain reliability. And so on. Every requirement leads to one or more specifications that acceptable luminaires must satisfy for the project to succeed.
Specifications follow from requirements. A specification that does not match-up with a requirement is an artificial constraint that reduces the flexibility needed to help the project succeed. By robbing the engineers of flexibility to develop a solution, specifications that are not traceable to requirements almost always increase project cost and make it harder – sometimes even impossible – for the project to succeed.
What are Standards?
Standards are an agreed-upon way of doing things to meet a broad goal: e.g., inter-operability, or safety. The cable that connects your mobile phone to its charger conforms to a standard. The order of the red, yellow, and green lights in a traffic signal is a standard. The use of 120 VAC to power an electrical device is a standard. The design of an electrical socket and matching plug conform to a standard. Other ways of doing the exact same thing may exist: a standard is simply the agreed-upon way of doing the thing.
Standards are independent of project specifications or requirements. Requirements define success for a particular project. Project specifications, which derive from project requirements, are how you know that what you are building, or purchasing, is advancing you toward project success. Standards provide a common language for describing specifications and simply the process of describing project specifications.