Parameter: si

This is the person who has some responsibility for the data.  Can be the ultimate responsibility, i.e. Principle Investigator or Chief Scientist, or can be a scientist who is responsible for one kind of data, or data collection or analysis or identification.  This is not  the person who wrote the numbers or observations in the log. That is 'recorder'. Some of the previously labelled 'person' designations are now 'investigators'.