title: Semantic Indexing of Medical Learning Objects: Medical Students' Usage of a Semantic Network.
abstract: BACKGROUND
  The Semantically Annotated Media (SAM) project aims to provide a flexible platform for searching, browsing, and indexing medical learning objects (MLOs) based on a semantic network derived from established classification systems. Primarily, SAM supports the Aachen emedia skills lab, but SAM is ready for indexing distributed content and the Simple Knowledge Organizing System standard provides a means for easily upgrading or even exchanging SAM's semantic network. There is a lack of research addressing the usability of MLO indexes or search portals like SAM and the user behavior with such platforms.
  
  
  OBJECTIVE
  The purpose of this study was to assess the usability of SAM by investigating characteristic user behavior of medical students accessing MLOs via SAM.
  
  
  METHODS
  In this study, we chose a mixed-methods approach. Lean usability testing was combined with usability inspection by having the participants complete four typical usage scenarios before filling out a questionnaire. The questionnaire was based on the IsoMetrics usability inventory. Direct user interaction with SAM (mouse clicks and pages accessed) was logged.
  
  
  RESULTS
  The study analyzed the typical usage patterns and habits of students using a semantic network for accessing MLOs. Four scenarios capturing characteristics of typical tasks to be solved by using SAM yielded high ratings of usability items and showed good results concerning the consistency of indexing by different users. Long-tail phenomena emerge as they are typical for a collaborative Web 2.0 platform. Suitable but nonetheless rarely used keywords were assigned to MLOs by some users.
  
  
  CONCLUSIONS
  It is possible to develop a Web-based tool with high usability and acceptance for indexing and retrieval of MLOs. SAM can be applied to indexing multicentered repositories of MLOs collaboratively.
authors.affiliation: Division of Knowledge-Based Systems, Department of Medical Informatics, RWTH Aachen University, Aachen, Germany. ntix@mi.rwth-aachen.de.
authors.forename: Nadine
authors.identifier: http://orcid.org/0000-0002-2421-1721
authors.initials: N
authors.lastname: Tix
authors.forename: Paul
authors.identifier: http://orcid.org/0000-0002-5200-0059
authors.initials: P
authors.lastname: Gießler
authors.forename: Ursula
authors.identifier: http://orcid.org/0000-0003-3438-982X
authors.initials: U
authors.lastname: Ohnesorge-Radtke
authors.forename: Cord
authors.identifier: http://orcid.org/0000-0002-7301-1566
authors.initials: C
authors.lastname: Spreckelsen
keywords: learning objects; medical education; semantic indexing; semantic net; usability evaluation