Sublime

though there was no compelling need to do so.

and focus resources in an efficient manner.

Perceptibility is achieved when everyone can perceive the design, regardless of sensory abilities.

and mental models of how people interact with systems (interaction models).

As the flexibility of a system increases, the usability of the system decreases.

In both cases, the high degree of convergence indicates a stable environment—one that has not changed much over time—and designs that closely approximate the optimal strategies afforded by that environment. The

When time and resources are limited, resist efforts to correct and optimize designs beyond the critical 20 percent, as such efforts yield diminishing returns. Generally,

Simplicity is achieved when everyone can easily understand and use the design, regardless of experience, literacy, or concentration level.