Richard's points about unifying to observations are very good and relevant to use. Indeed reexamination possibilities are not 100% dependent on collection versus observation-only data. The reexamination of a film or still picture is somewhat intermediate between the reexamination of field notes and of an actual specimen. Certain questions can be asked, others not. However, the main point is that these are properties of the observation and that more cases exist than museum or not.

I basically disgree about assigning GUIDs to physical objects, if these are not unambigously attached to the object, rather than to one of possibly several data records. I have no problem if a barcode or RFID is a GUID rather than a local ID. I think it is not practical to demand all museums to change their physical system to a GBIF-chosen accession numbering system. It certainly would simplify life - I agree about desirability!

I'm not sure I understand the question. I guess I would answer with another question: How does a Social Security Number (SSN) for a U.S. Citizen > get attached to an individual person? I don't think anyone would think of a SSN as an identifier for a data object -- it is a unique identifier for the physical person.

Yes, but the association problem is solved here - and NOT by unreliable secondary data. You can ask a person to show you the government-produced SSN-card, which is at least somewhat difficult to falsify. If you can do the same with a physical specimen object - no problem. If you cannot, and have to "guess" the GUID by maiden name and last known address, SSN would be in trouble.

Gregor---------------------------------------------------------- Gregor Hagedorn (G.Hagedorn@bba.de) Institute for Plant Virology, Microbiology, and Biosafety Federal Research Center for Agriculture and Forestry (BBA) Königin-Luise-Str. 19 Tel: +49-30-8304-2220 14195 Berlin, Germany Fax: +49-30-8304-2203