Skip to end of metadata
Go to start of metadata

General Principles

Verbs are a critical component in xAPI statements because they link the Subject and Object clauses. It is most important part about which to be consistent. As noted by Andrew Downes in the original TinCan Registry, "It creates problems if there are many different identifiers for a verb, activity, attachment or extension that mean the exact same thing." So before creating a new Verb, look to see if there is an existing one and if it is a close enough fit for your intended purpose. 

The same can be said of Profiles. If there is an existing Profile that is good enough, try to resist the temptation to create a whole new Profile. There are some useful tips on using or creating a Profile here. An advantage and also disadvantage of xAPI is that it is very flexible and extensible, with a very open architecture. However, while it is nice not to be locked down into a particular structure, there is also a Tower of Babel effect with too many competing Profiles. 

Sometimes you have to decide whether to use or modify an existing Verb, or whether to create a new Verb. In considering this, ponder also on other factors (Are you a Lumper or a Splitter? Is it better to be able to group similar activities and Verbs, or to be able to split them up easily?). This is even more important if you plan to go to the next stage with xAPI and use it to analyze activities that are measured across a number of domains or input sources.  

Finding verbs

  • Look at ADL verbs and the Tin Can registry to see if there is a good fit.
  • Look at other profiles on to see if there is a good fit (there may be a tool soon that facilitates searching across profiles).
  • If a scope note for an existing verb is necessary, that can be added. A scope note provides auxiliary metadata for the community of practice/profile, but anyone using the verb IRI would see the standard description of the verb without the scope note.


Process for creating new verbs

  1. We specify a medbiq URL, or at least what we want the url to be. We will use the following root path:
  2. We send Jason Haag verb metadata and recommended URL. Metadata will include label, description, ID/IRI, closely related term, and vocabulary (

If we decide that an existing verb would work if a scope note was added, we could likely add that and would contact Jason to do so. This process will be changing as we move across to using GitHub as a repository and version control system for Profiles. There are some quite good tips on getting started here



Verb Template




Closely Related Term



User has visited a node within the VP case. Not necessarily same as 'read' or ‘experienced’ because an internal rule or trigger might immediately bounce them on to another node or activity. (See ‘Launched’). So, while the user may have landed on that node, if they are immediately redirected, they may not even see that page/node. Can be used for a physical or virtual location. or Visited


User has ignored a flag or other virtual patient data. This is a flag or action sent by either a facilitator or the VP player engine to indicate that an action was expected by this point in time and had not occurred. Sometimes this is a good thing, and while absent, is not necessarily a negative aspect - for example, if there is a distractor in place that the actor is supposed to ignore as irrelevant. or


VP player engine has changed a counter value. This may be triggered by arrival at a particular node, or by a rule within the case design created by the virtual patient author, or by a timer expiration point. Although the counter value may be regarded as a score, note that the ADL verb ‘scored’ is overall score for the case or exam (, which is not the same thing. or

Rewound SeekedUser has moved forwards or backwards on the timeline of a video or audio segment, with the presumed intent of playing that segment again. Note that the action of playing that segment again is indicated by the Played verb, and is not assumed to happen as part of the Rewound Seeked verb. For a rewind, the time point will be earlier in the video.


Have not found one yet. Suggestions?




  • No labels