On 05/04/12 15:11, Sofia Khatoon wrote: Right; in general, auxiliary Snaks would always provide a fallback for complex cases. However, we also intend to provide direct support for units of measurement in the system (now part of the NumberValue). Automatic unit conversion is required to support language-independent editing in many cases, so it follows from the goal of Wikidata to be internationalized. Annotations regarding the precision of values should also be supported, but the details have not bee finalized yet. The system will most likely not be elaborate enough to capture detailed scientific information (which may vary from case to case). Auxiliary Snaks are really the way to go there. The simplest form could be a translatable note that provides details in unstructured form; more formal solutions could make sense in disciplines where many values have the same kinds of extra data attached. But already simple things like population figures will at least need comments (estimate or census? which area was considered? when was this measured? etc.) The system will be flexible enough to work out the best ways for doing such things in each domain without having to make a decision upfront. The combination of limited precision and unit conversion bears some challenges to get a sane editing behaviour across languages and there is still some conceptual work to be done there. Markus