information content entity record of missing knowledge A statement in a journal article indicating that the age of a patient at the onset of disease is not known. A statement indicating that the weight of a mouse was not measured. Bjoern Peters This class should probably end up in IAO. It could be further breaken down to indicate different kinds of lack of knowledge, e.g. inability to determine something vs. no attempt made to determine something vs. no informatino available if it was even attempted to determine something. The design pattern should be generalizable. 'unknown sex' is the first example, and needed immediately. a information content entity created to indicate that information about something is not available to the person recording it. record of missing knowledge metadata complete