Usability Components: Learnability and Usability
According to Jakob Nielsen and Ben Schneiderman, a usability expert and a computer scientist the components of usability are learnability, efficiency [of use], memorability, [few and non-catastrophic] errors, and [subjective] satisfaction.
Learnability - A website’s learnability is simply how easy users can understand the layout of the web site design and so be able to do whatever task they have set out to do when they visit the website on their first time. A website that has good usability in terms of learnability has an intuitive design so that the majority of its users will be able to find what they need easily. For example, a a site is learnable if a user that wants to make a purchase easily see the buy button and is able to fill out necessary field easily. A website that is not that learnable will result in the user having to look around for the way to make a purchase spending much time doing this or in the end deciding not to make the purchase.
Efficiency - A website design is efficient if users are able to perform their tasks quickly. Learnability and efficiency goes hand-in-hand. Learnability is how fast users can understand and learn your website’s structure so they can navigate around the website easily while efficiency is the number of steps a user must take in order to get to their goals. Let us use the example of buying to further illustrate what efficiency of use is. Two website’s can both be equally learnable if the main page has a similar interface with the buy button placed in a prominent area, making it easy to make a purchase. However, efficiency can still differ if one site only take one or two steps to actually finish making the purchase while the other site takes multiple steps (such as filling out endless forms) in order to finish the task. Of course, the more efficient a site is the better the design is since it will eat up less of the users’ time.