Many of these principles have a strictly physiological basis. Finally, evaluation principles focus on the questions that authors of computer-based instructional materials must answer to evaluate the effectiveness of the design decisions that they have made. Principles here are mostly methodological, and do not attempt to interpret the results. It is important, when attempting to distill common principles from so many sources, that design principles be distinguished from design guidelines . Design guidelines appear frequently in industry sources.
Guidelines are rules.
They tell the designer, for instance, to always use blue in the logo. Their goal is consistency and predictability. Often, these rules have been followed by large teams working on a single project for a single company. The success of guidelines is usually measured by the success of the projects themselves. We attempt to avoid design guidelines in the text.