Operating instructions are written so that a process, a procedure, a plant, or a piece of equipment can be operated unhesitatingly, accurately, and economically. The instructions must therefore be:

To meet these requirements, it is necessary to go beyond consideration of style. We must consider the selection, arrangement and physical presentation of information; we must have in mind constantly the frames of reference of the receivers, their levels of expertise, their past training (if any), and the contexts in which the instructions have to be used.