Seems there is the possibility of pragmatic agreement here, so I won't cut off at this point...

On 26 November 2010 08:18, Edward C. Zimmermann <[log in to unmask]> wrote:
On Fri, 26 Nov 2010 07:00:45 +0000, Simon Grant wrote

> It might be more useful to separate the source of any uncertainty from the
> statement of how uncertain it is.

That's asking for too much. The source does not matter.

Despite these protestations, I think there is actually room for agreement here.
All we have done is
to break down "uncertain" to two subjective and personal types: 

1) Questionable. I have a date but I'm not sure--- or even that I suspect that
  the date is wrong.

This would seem to me to interoperate nicely with what I characterised as "guesstimate" but didn't want to use that term. I would also prefer not to use the term "questionable". It means, in my terms, "here is a date, but there are (a) no guarantees about its accuracy and (b) I'm not prepared to give you any definite range within which I believe the true value lies" 

2) Unknown. I don't have a date with sufficient precision yet. 198u, for
  example, means that I know it was in the 1980s but hope to, at some later
  time (state of knowledge),know.
and a data collection type
3) I've not yet collected the data. 198| (to use MARC syntax) means that I've
  not yet gotten around to collect the date (incomplete).

198| expresses that the date shall be updated to include its year at some point.
198u tells us that, at this time, we don't know the year.
(1985)? tell us that we think its 1985 but are not sure. 

Pragmatically I would handle 198| and 198u as 1980 decade precision.
(1985)? says something else. Its not even saying with certainty that the
event took place in the 1980s.

Having separated out the "guesstimate" as something we might agree on separately, I *think* the rest of this position is compatible with having just one representation, not two. Operationally, pragmatically, I cannot see a difference in a value as presented. The difference as expressed here is to do with future intentions, and I don't believe we should be attempting to represent anything to do with future intentions. 

However, in both cases this states a claim or belief that the actual value is one of the set running all the way from 1980 to 1989. I don't see any *pragmatic*, *operational* reason for making a distinction. Furthermore, I believe that if such a distinction were made, in practice people would argue over or confuse the two, leading to inconsistency of semantics. The consequence would be that in practice, both forms would have to be treated equally in any case.

We could be crazy and add grade of certainty and data-quality:

Thanks, but I agree this looks crazy enough to leave well alone. 

Simon Grant
+44 7710031657