Nielsen and Mack (1994) and Nielsen, Molich, Snyder, and Farrell (2001) have
published usability heuristics (or rules of thumb) based on their thousands of
usability tests of interfaces and, later, tests of ecommerce Web sites. They include
visibility of system status, match between the system and the real world, user control
and freedom, consistency and standards, error prevention, reconnection rather
than recall, flexibility and efficiency of use, aesthetic and minimalist design,
help that users recognize, diagnosis and recovery from errors, and help and documentation.
Some of these are already familiar to you from the input and output
design chapters.