In thinking about the contents of each matrix entry, we can ask the following questions.
• What are the effects of unintentional errors? Consider typing the wrong command, entering the wrong data, using the wrong data item, discarding the wrong listing, and disposing of output insecurely.
• What are the effects of willfully malicious insiders? Consider disgruntled employees, bribery, and curious browsers.
• What are the effects of outsiders? Consider network access, remote access, hackers, people walking through the building, people snooping at coffee shops, and people sifting through the trash.
• What are the effects of natural and physical disasters? Consider fires, storms, floods, power outages, and component failures.