Exploratory PICS Rating System

A PICS rating system is a file (standard extension is .rat) that represents a set of categories and vocabulary used to assess a particular domain.

In our case, the domain is the level of accessibility of web pages.

This can be used in multiple ways, for instance by search engine (as in: give me all the pages about that *and* that are "Non Graphical Access Level" < 2) or just as a storage format in a static database of page rating.

The most difficult part if to come up with a semantic mapping as to what the various scale level means (Fully accessible, Mostly accessible, etc) and this is clearly a task for the newly formed WAI Evaluation&Repair Interest Group.

In this prototype, we have defined 2 categories:

• Non Graphical Access Level
• No Audio Access Level

Each category has a 5 scale-value:Fully,Mostly,Poorly accessible and Mostly, Fully inaccessible

Here is the full access.rat file.

((PICS-version 1.1)
 (rating-system "http://www.w3.org/LabelBureau/WAI")
 (rating-service "http://www.w3.org/Ratings/WAI")
 (name "WAI")
 (description "The Web Accessibility Initiative (WAI) rating service for the Internet")

 (category 
  (transmit-as "ng")
  (name "Non Graphical Access Level")
  (description "Level of access to the information on a page for a
	        user agent with no graphical screen capability")
  (label
   (name "Full")
   (description "Fully Accessible without a graphical screen")
   (value 0) )
  (label
   (name "Most")
   (description "Mostly Accessible without a graphical screen")
   (value 1) )
  (label
   (name "Poor")
   (description "Poorly Accessible without a graphical screen")
   (value 2) )
  (label
   (name "Bad")
   (description "Mostly Inaccessible without a graphical screen")
   (value 3) )
  (label
   (name "None")
   (description "Completely Inaccessible without a graphical screen")
   (value 4) )
  )

 (category 
  (transmit-as "na")
  (name "No Audio Access Level")
  (description "Level of access to the information on a page for a
	        user agent with no sound capability")
  (label
   (name "Full")
   (description "Fully Accessible with no sound")
   (value 0) )
  (label
   (name "Most")
   (description "Mostly Accessible with no sound")
   (value 1) )
  (label
   (name "Poor")
   (description "Poorly Accessible with no sound")
   (value 2) )
  (label
   (name "Bad")
   (description "Mostly Inaccessible with no sound")
   (value 3) )
  (label
   (name "None")
   (description "Completely Inaccessible with no sound")
   (value 4) )
  )
)

Labels are encoded in PICS in the form of:

 (PICS-1.1 "http://www.w3.org/Ratings/WAI" labels
  exp "1997.12.31"  for "http://www.foo.com/foo.html"  by "DD" 
  ratings (ng 1 na 0))

meaning the page http://www.foo.com/foo.html has a

• Non Graphical Access Level" value of Mostly accessible (1) and a
• No Audio Access Level" value of Fully accessible (0).

Since modern browsers already implement the PICS standard, we can try out this access.rat file in Microsoft Windows Internet Explorer for instance, and look at the generated User Interface.