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There is a technical matter I need to raise, but first, an update.

 

The work on a Committee Draft of ISO 8601 Part 2 is progressing nicely and it might be available for comment within several weeks (although with ISO, you never know what sort of administrative matter might hold things up).  The plan is that 8601 Part 2 will include all of  EDTF levels 1 and 2 functionality (all functionality retained; some changes in syntax) at least for the Committee Draft; it is impossible to predict what will survive the balloting process.   The main body will not mention or refer to EDTF. It will however define the two levels (1 and 2) and indicate that these levels are defined for reference by profiles.   There will be an Annex (informative) for “Community Profiles of ISO 8601”.  The Annex will be two parts: the first will describe profiles in general. The second will be the EDTF profile, which will define the three levels (0, 1, and 2), explicitly listing the level 0 features, and calling out the main body to describe levels 1 and 2.  Of course EDTF will be the only profile, initially, but there will be procedures for adding other profiles.

 

The technical matter: ISO wants the term “precision” replaced by “accuracy”.  I have objected to this change and I would like to hear your views.

 

The request for this change is based on http://www.astro.lu.se/Education/utb/ASTM11/lecture2.pdf   which I don’t think justifies it at all.

 

Following is part of my objection which I submitted:

 

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I'm sorry but I disagree with the change from precision to accuracy.

…….   I have researched this a bit further and I conclude that precision is correct. For example see

https://www.ncsu.edu/labwrite/Experimental%20Design/accuracyprecision.htm

 

“Accuracy refers to the closeness of a measured value to a standard or known value. For example, if in lab you obtain a weight measurement of 3.2 kg for a given substance, but the actual or known weight is 10 kg, then your measurement is not accurate. In this case, your measurement is not close to the known value.

“Precision refers to the closeness of two or more measurements to each other. Using the example above, if you weigh a given substance five times, and get 3.2 kg each time, then your measurement is very precise. Precision is independent of accuracy. You can be very precise but inaccurate, as described above. You can also be accurate but imprecise.”

 

So let’s say the “actual” date is 1965-07-07.   Then an estimated date of 1965-07-06 is more accurate than 1965-07-05.   If we estimate that date with “month precision”  we get 1965-07, and we will get 1965-07 whether the actual date is 1965-07-07, 1965-07-06, 1965-07-05 or any other date in that month.  So, for any date in that month, 1965-07, in terms of decade precision is precise.   “Month” is then a measure of precision, not accuracy.

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Anyway I welcome opinions on this, it is quite possible that my reasoning is faulty.  If nobody responds I will assume nobody cares, and I will drop the objection.

 

Ray