The analysts use two devices to make it easier to write their specification. The first device, the requirements specification template, is an outline and guide to writing a requirements specification. The business analysts use it as a checklist of the requirements they should be asking for, and as a consistent way of organizing their requirements documents. The second device is a shell, also known as a snow card. Each atomic (that’s the lowest level) requirement is made up of a number of attributes, and the snow card is a convenient layout for ensuring that each requirement has the correct constituents.
Link · 2. The Requirements Process