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Re: Usability testing of XML vocabularies?

• From: Rick Jelliffe <rjelliffe@a...>
• To: "Costello, Roger L." <costello@m...>
• Date: Mon, 07 Jul 2008 18:04:31 +1000

Costello, Roger L. wrote:
>  
> How do the standards bodies - W3C, OASIS, ISO - conduct usability
> testing on the XML vocabularies they produce? 
>   
I am not aware of formal usability testing ever having been done on XML.

Plausible theories might include:

1) One chunk of the population is devoted to voodoo or faddish theories 
about markup (e.g. attributes = bad)
2) Another chunk thinks that users never see the XML and so it doesn't 
matter
3) Another chunk is constrained to use schema languages that only allow 
some kinds of constraint, so they run up against brick walls whenever 
they try to get too idiomatic (in which case they just ignore schemas: 
e.g. old RDF, XSLT, SVG)
4) They are modeling pre-existing data objects: e.g. a schema or data 
structure exists, and it might be too messy to fit neatly into an 
optimal model (MS' Jean Paoli told me this was the difference between 
Office 2003's XML and Office 2007's XML: they first tried to get nice 
XML and found it was just to difficult to shoehorn all the ideosyncratic 
stuff in.)
5) There is a clear tree of the data or the report. (See the Michael 
Stonebraker ACM article VLDB ’07, "The End of the Era (Its Time for a 
Complete Rewrite)" which questions the relation model by saying how 
often, in fact, schemas are stars, snowflakes, trees, streams, etc.

But the *main* reason it is difficult, I think, is that usability 
testing implies a scenario and task. You don't just sit people from the 
street down and say "do you understand this document?" (Actually, that 
was one of the problems with OOXML: so many people wanted that to be the 
criterion.) One of the value propositions of XML is retargeting in the 
future to unknown tasks.

So, in that case, rather than user testing now, practitioners tend to 
regard future-proofing as a better option: look at how schemas tend to 
change as they evolve, and start off down that road now. For example, 
schemas tend to get looser over time, they tend to get more genericized 
and consistent, and they tend to be bundled into versions or dialects, 
which at worst require different schemas and tools. The logical response 
to this is to start off with a generic and open/extensible schema, and 
to put version constraints as another layer (you guessed it...Schematron).

In SGML days, there was in fact some user modeling, even using Fitts 
law. This was because the prime cost then was regarded as keystrokes by 
typists, so the different forms of minimization could be tested to get 
the most efficient data entry. This was sometimes measured in 
"keystrokes per tag" (i.e. effective tag) and it was not uncommon to 
have less than one keystroke per tag. But this was because there was 
clearly a bottleneck or critical path scenario identified. But the XML 
consituency has no awareness of data entry efficiency as a scenario: I 
don't recall it ever having been mentioned, or only in passing to 
comment that XML prizes readability over efficiency: in effect XML 
embodies a proposition that the critical path is developer 
ease-of-comprehension not data entry.

Cheers
Rick Jelliffe

• References:
  • Usability testing of XML vocabularies?
    • From: "Costello, Roger L." <costello@m...>