When a user first experiences an application, it takes some time to figure out the interface, controls and how to perform tasks. As the user continues to perform similar tasks, she learns how to operate the application more effectively and saving time. Learnability is according to Wikipedia:
the capability of a software product to enable the user to learn how to use it. Learnability may be considered as an aspect of usability, and is of major concern in the design of complex software applications.
But how do one measure learnability? My idea is to let a number of users perform similar tasks on the same application, measuring the time it takes to perform tasks. My hypothesis is that the time to perform similar tasks will be quicker the more similar tasks she performs up to a certain level where the user doesn’t learn more.
If I were to compare the learnability between two different applications, per example travel agencies web sites, and letting users find a certain hotel in a certain place. Then I would (assumable) get a graph looking like the following:
Reading from the graph one could say that Agency 1 have better learnability than Agency 2 but that Agency 1 is harder to use for new users. Over time Agency 1 will be faster to use.
Is this a fair measurement on Learnability? Could I measure Learnability in a better way?