Categorize each of the following usability specifications as a performance measure or a preference measure. Justify your answers.

a. Users should be able to login in within 3 minutes, even if they forget their passwords.
b. On a scale of 1 to 5 where 1 is “very difficult” and 5 is “very easy”, ninety percent of the users should rate the login process a 4 or above.
c. Users should hit the “back” button no more than 2 times when looking for merchandise items.
d. Over 95 percent of our current users will prefer the redesigned site to the current site.
e. Users should be able to find the “check out” page in one click no matter where they are in the site.
f. If they have shopped online previously, users should be satisfied with the security of our site’s online transaction system.

a. This is measuring a user behavior, which is directly observable. This is a performance measure.
b. Asking a user to offer a judgment or rating about a system is a characteristic of a preference measure.
c. The act of hitting the “back” button is directly observable. This is a performance measure.
d. The word “prefer” indicates that this is a preference measure.
e. This is a performance measure because an observer can watch a user search for and click on a link.
f. The word “satisfied” indicates an opinion, which makes this a preference measure.