        * @property title
       ###
       title:
-        # TODO - get the Session title template from a labels.cfg
-        # entry:
-        #   [Session]
-        #   label=Session
-        # and include the label in the format below. Thus, the
-        # title could be externally configurable to include, say,
-        # 'Visit', rather than 'Session'. See also the subject.data.coffee
-        # title TODO.
         get: ->
           "#{ @subject.title } Session #{ @number }"
+
+      ###*
+       * The inclusive one-based number of days from the first
+       * session date to this session date.
+       *
+       * @property day
+      ###
+      day:
+        get: ->
+          @date.diff(@subject.sessions[0].date, 'days') + 1
 
       ###*
        * The [_parent_, {session: _session_}] path, where:

      path:
        get: ->
          @subject.path.concat([{session: @number }])

    ###*
     * @method hasDetailProperties

    session

`export { Session as default }`
