Re: "scheme" attribute of META element

On Wed, 19 Aug 2009, Tom Dent wrote:
> On Thu, Aug 13, 2009 at 12:19 PM, Ian Hickson<ian@hixie.ch> wrote:
> > On Tue, 4 Aug 2009, Tom Dent wrote:
> >> On Wed, Jul 29, 2009 at 7:27 PM, Ian Hickson <ian@hixie.ch> wrote:
> >>
> >> The scheme does not directly impact on the user, but can (for 
> >> example) do so via search software.  You can see a view of IPSV at 
> >> http://www.esd.org.uk/standards/ipsv/viewer/ or LGSL at 
> >> http://www.esd.org.uk/standards/lgsl/viewer .
> >>
> >> If a user searched for pages by using a "non-preferred term", the 
> >> search engine should convert that to an IPSV preferred term and then 
> >> return all content with that preferred term in its metadata (with the 
> >> IPSV scheme). The search software might also suggest showing content 
> >> for broader and narrower subject headings from the IPSV hierarchy.
> >>
> >> The LGSL is being used to reference local authority sites in the UK 
> >> Government's Directgov site (at http://www.direct.gov.uk/) which is 
> >> used as a portal to local authority sites, and uses LGSL to reference 
> >> pages.
> >
> > This doesn't really seem like a very compelling use case. Surely more 
> > modern search technologies would be a significantly more effective way 
> > of addressing the same problem at the user level, but with a 
> > significantly better user experience? Can you walk me through what a 
> > typical user might search for in a way that metadata with a scheme 
> > would affect the result? I'm having trouble figuring out what a 
> > suitable "non-preferred term" might be. For example, I did a search on 
> > direct.gov.uk for "how do i report foreign income for tax purposes", 
> > which gave me the same top result as Google did for that same search 
> > (with a site restrict), and did not appear to be in any way affected 
> > by metadata terms that used schemes.
>
> Using the LGSL metadata can make the seach at the Directgov site more 
> powerful than Google. For example, this page about abandoned vehicles 
> references LGSL: 
>
> http://www.chiltern.gov.uk/site/scripts/services_info.php?serviceID=306&startsWith=A
>
> <meta name="eGMS.subject.service" lang="en" scheme="LGSL"
> content="Abandoned vehicles" />
>
> Doing a Google search for that abandoned vehicles and a postcode in that 
> authority does not return the correct page: 
> http://www.google.co.uk/search?hl=de&q=HP5+1RS+abandoned+vehicles 
> However entering your postcode into the Directgov site (which also 
> references the LGSL in the URL) does:
>
>  http://local.direct.gov.uk/LDGRedirect/LocationSearch.do?searchtype=1&LGSL=372&LGIL=0&Style=&formsub=t&text=HP5+1RS

You don't need the "scheme" attribute to do that, though. This is 
basically just synonym matching; you could apply the same synonym matching 
to all terms on the page, and to all metadata values, regardless of the 
scheme="" attribute.

(How do you map the postcode to that page, by the way?)


On Wed, 19 Aug 2009, Mike Thacker wrote:
>
> As I understand it, this thread is concerned with the usefulness of 
> keeping the "scheme" attribute of the META element.
> 
> The discussion comes down to whether or not schemes defining the format 
> of values or, as described here, controlled lists adding definition and 
> precise meaning to values (in the "content" attribute) are useful.
> 
> To me adding defining the controlled list from which a precise value is 
> taken has tremendous value, as described by Tom.
> 
> Ian you say:
> 
> >>Surely more modern search technologies would be a significantly more
> effective way of addressing the same problem at the user level, but with 
> a significantly better user experience?<<
> 
> Can you say (or provide a link to indicate) what these modern search 
> technologies might be?

Well for example in this particular case it's not clear that the scheme="" 
attribute is helping at all. Surely it would be better, as noted above, to 
just apply the same processing to _all_ the keywords on the page, rather 
than just those in the metadata headers, regardless of scheme="".

-- 
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