daniel added a comment. In https://phabricator.wikimedia.org/T105623#1656325, @Mike_Peel wrote:
> As posted on wikidata-l, taking the current approach of +- 1 SF is a really > bad idea. As an example, say you have a length of 100m. Which significant > digit do you assume is correct? Is this +- 100m, 10m or 1m? What if it's > referring to the length of a 100m run, where the accuracy could be much > higher than the significant digit given, e.g. 100m +- 1cm? Or what if it's > the size of a crater on a distant planet, where it might be 100m+-50m? Or if > the actual value is 100m +- 3m, but we say that it's +- 1m (which I see is > the default in this case), which might be believable to readers but very > misleading in reality? The problem with defaulting to +/-0 or "unknown" significance is that we can't apply rounding - and if we can't apply rounding, we can't apply conversion without introducing false precision. For example, 2m +/-0 would convert to 6.56167979ft +/-0. This implies a precision to sub-micron levels, which would very likely be wrong, and also not useful in infoboxes. If however we assume 2m+/-0.5, that converts to 7ft (+/-1.6). That's much more sensible, and avoids false precision. If we did not plan to support unit conversion, I would be ready to go along with your argument. We would simply say we don't know th precision. With unit conversion however we can't do this. And relying on the conventions for specifying significant digits seems the best we can do. > If there's no uncertainty given, then please just say that rather than trying > to make one up! We are not making one up. The precision is given implicitly in the decimal notation of the number, using the convention of significant digits. This is quite unambiguous for cases like 3.20 (three significant digits) or 2.3e3 (2300 with two significant digits). It's ambiguous for input like 200 or 1700 - there's a good chance that the zeros are insignificant, but we don't really know. We should improve our UI to help the user with correct input. TASK DETAIL https://phabricator.wikimedia.org/T105623 EMAIL PREFERENCES https://phabricator.wikimedia.org/settings/panel/emailpreferences/ To: daniel Cc: Mike_Peel, Jc3s5h, thiemowmde, kaldari, daniel, Stryn, Lydia_Pintscher, Liuxinyu970226, Snipre, Event, Ash_Crow, mgrabovsky, Micru, Denny, He7d3r, Bene, Wikidata-bugs, Ricordisamoa, Kelson, MSGJ, Klortho, Wolfvoll, Aklapper, aude _______________________________________________ Wikidata-bugs mailing list Wikidata-bugs@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikidata-bugs
