If a system is not usable, security could suffer as users will try to minimize the effort required to provide input for authentication, such as writing down their passwords on paper.
Users accept the security measures only up to a certain point before becoming annoyed by complicated authentication mechanisms.
[2] The UDS framework looks at three broad categories, namely usability deployability and security of a web authentication system and then rates the tested system as either offering or not offering a specific benefit linked to one (or more) of the categories.
While a lot of research regarding web authentication system is currently being done, it tends to focus on security and not usability.
[1] Future research should be evaluated formally for usability using a comparable metric or technique.
A study conducted in 2015[2] found that users tend to prefer Single sign-on (like those provided by Google and Facebook) based systems.
[2] Single sign-on based systems have resulted in substantial improvements in both usability and security.