You'd use journaled sessions when you need detailed information from the remote tests; for example, the actual mouse movements or sequence of dialog boxes and menu items accessed by the user. Obviously, requesting the user to record all of their actions in a log, down to each individual click, is out of the question. (Although if you're lucky enough to get someone who's anal enough to do that, well, just think, is that guy representative of your user population? Good luck...)
Self-reporting logs, therefore, are best used when you don't have the time or resources to provide the interactive package required for journaled sessions, or when the level of detail provided by journaled sessions isn't needed. For example, you might want just general perceptions and observations from a broad section of users.
The main disadvantage of this technique is that there is no observer to "see" what the user is doing--the facial expressions of the user, or even spoken comments inadvertently expressed during difficult portions of the session.
Of course, provide a pre-paid mailing envelope for your evaluators to return their log.
Castillo, José, Remote Usability Evaluation Home Page, 1998.
José has a ton of remote evaluation stuff on his page.
Engineering, 1993, Academic Press/AP Professional, Cambridge, MA
ISBN 0-12-518406-9 (paper)
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