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Ed, 

 

You raise two issues:  

 

(1) The default should be "unstated reliability" rather than "certainly
unknown" as I had suggested.    That's fine with me.  So '1984?'  would
carry the implicit semantics "uncertain, but level of uncertainly unstated".

 

(2) Extensibility or not.  There are two ways to do this, I think. One is to
declare this model to be explicitly non-extensible and define a closed
controlled vocabulary.  The other would be a model based on assigning URIs
for the levels. 

   The first is what I thought you wanted, and since you are perhaps the
only member of this forum interested in uncertainly - that is, going beyond
simply asserting that a value is uncertain, and actually assigning an
uncertainly level - then my only interest is in ensuring that whatever model
we adopt, it does not affect those who simply want unqualified uncertainly.
And if a closed, controlled vocabulary meets your needs - and it certainly
does seem to be the least complex approach - then I think it's fine.
However, if you want the model to be extensible (and presumably we would
want decentralized extensibility) then I think we need to  allow a URI
within the string where the URI identifies a level of uncertainty.  Do you
want to pursue this approach?

 

--Ray

 

 

 

From: Discussion of the Developing Date/Time Standards
[mailto:[log in to unmask]] On Behalf Of Edward C. Zimmermann
Sent: Friday, February 04, 2011 2:27 AM
To: [log in to unmask]
Subject: Re: [DATETIME] uncertainty and precision

 

On Thu, 3 Feb 2011 11:24:30 -0500, Ray Denenberg, Library of Congress wrote 
> (I changed subject of this thread, it was "uncertainty".)

I would change the topic to "data reliability". Uncertainty is an attribute.
Precision is also something else.. 

> Take "uncertainty" first.    If we say that ? may be followed by a measure
of uncertainty we have to be careful because ? does not always end the
entire string.  For example: (2004)?06-1.  However if we say that
uncertainty is indicated by one of the letters a, b, c, d, e, then we don't
introduce ambiguity because in the current draft there isn't any case where
? would be followed by one of these letters. 


> 

  


> So the question is:  Are Ed's suggested set of values acceptable to
indicate uncertainty: 


> - a) Known to be correct (observed, documented etc.) 
> - b) Likely correct ( p> 50%) 
> - c) Possibly correct (Might be but not likely) 
> - d) Likely incorrect (The date is expected to be wrong p ~ 0) 
> - e) Unknown (certainty unknown). 


> Actually I would eliminate (e); "certainty unknown" should be the default
- it should not be mandatory for the ? to be followed  by an uncertainly
level.  


>  

 

1) I think the default is "unstated reliability". For the reciever there is
perhaps little difference but they are not the same just as the (a) case is
equivalent to the reciever but not the "same" as the non-specified case,
e.g. (X)?a versus (X)

2) I am not quite sure that using letters is the best approach since it
locks things too much down and prevents extension... I can well envision
profiles where people have finer semantics such as "most certainty correct
(but possibly wrong)". Recall these are also dependent upon states of
knowledge. The assertion, for example, that that the Earth was the center of
celestial spheres  was "known" to be correct and confirmed by observation
(including those of Ptolemy and Copernicus). Tycho Brahe established a new
standard of observations and that formed the basis for Keppler's work (and a
paradigm change)....


> Next, precision.  Similarly, ~ could be followed by a level of precision.
Simon, would you like to propose a scheme? 

 

Here we should to talk instead about "readability".

> 

  


> --Ray