When adding the call to action button for federated authentication to a service provider page, the following best practices are recommended.
Group all access options together and show the fewest possible number of choices.
Users can follow the right path faster when they can scan and differentiate available options at once. Access options might include: Access through your institution, Log-in (local account), Rent, or Purchase.
Clearly identify and communicate a primary access method.
Users’ success improves when they can clearly identify a single primary action. In many cases, federated access is the user’s best means of successfully accessing content and should be offered as the primary call to action. Other access options such as local account log in, rent or purchase, may be presented, but should not be weighted equally. For example, the primary access option should be a button and other choices might be links.
Place grouped access options in the first view of the page.
Getting full access to content is the primary goal for users. Users can rapidly identify the right path when the primary action is visible on the first page view. Whenever possible, avoid making the user scroll to locate access options. (Note: it is still appropriate to display options such as SP login in traditional locations such as the page header.)
Spread access options across different areas of the page. (Note: it is still appropriate to offer options such as SP login in traditional locations such as the page header.)
Give secondary access options (e.g., Purchase) equivalent visual weight as the “Access through your institution” button.
Place “Access through your institution” in a location that requires the user to scroll to find it.
Place “Access through your institution” on an overlay or separate page.
Give users a false sense of access by providing a PDF icon, Download, or View Article option on the article page when users must first authenticate before getting the full text.