SMART requirements

It is always interesting to have some kind of quality measure to check the quality of the work we are producing at a certain phase in the waterfall model.

For requirements, each requirement must respect the SMART quality attributes. Here are 2 very good sources explaining the acronym:

• http://www.win.tue.nl/~wstomv/edu/2ip30/references/smart-requirements.pdf (an old but still up to date paper on the subject)
• http://www.iibacolumbus.org/download/chapter_meetings/chapter_meetings_2013/01-09-2013_Kate_Gwynne.pdf (an IBM presentation on the subject).

The "5 lines summary" lies here (Source: ITGM):  

Software Requirements must have some characteristics to fulfill their goals.The most known is that they must be S.M.A.R.T.:  

Specific: A requirement must say exactly what is required (and shall not use weasel words).
Measurable: is it possible, once the system has been constructed, to verify that this requirement has been met ?
Attainable: is it possible, physically, for the system to exhibit that requirement under the given conditions?
Realisable : is it possible to achieve this requirement given what is known about the constraints under which the system and the project must be developed?
Traceable : is the ability to trace (forwards and backwards) a requirement from its conception through its specification to its subsequent design, implementation and test?

PS. Another classification that sometimes is applied to requirements is the MoSCoW requirements prioritization method.