I’m getting a little confused at this point. The title is “Absences and how they fit in the new data model”, and @abbybenson wanted to encourage absence data to be part of any new data model. Absences are data and they should be part of any sampling record.
There are, however, two kinds of sampling result that can be (and have been) described as “absence”. One is a “not found” result, which is an operational fact: the recorder either did or did not find the indicated taxon during a sampling event.
The second result is an assessment of the occurrence status of the taxon at the locality and on the date of the sampling event. This has nothing to do with other dates or with the general area. This assessment is an interpretation of the “not found” operational result, and as I hope I’ve demonstrated with examples, “not found” does not imply “not occurring at that locality on that date” (which is the same as “absent”). The taxon could be present at that locality on that date, but was missed in the sampling.
This assessment is not a guess as to whether or not the taxon was there. It is an assessment of the difficulty of deciding whether it was there. It is an assessment of the uncertainty of a “not found” result.
These two different sampling results - found/not found, and present/uncertainty of absence - should IMO be part of any new data model as separate categories. Darwin Core does not distinguish these two, with the result that “not found” is equated with “absent” in species distribution models and other statistical exercises, adding to the many other uncertainties in SDM modeling.
An assessment of uncertainty is a requirement of biological recording. We’ve used it for IDs, locations and time/date. What is the objection to applying uncertainty to a sampling result?
Is there a particular objection to using occurrenceStatus for sampling uncertainty? I’ve used it in this discussion because occurrenceStatus is currently flexible enough not to be binary (“can be extended by implementers with good justification”) and it’s “A statement about the presence or absence of a Taxon at a Location”, which (to me, at any rate) covers “uncertain about presence or absence because sampling was time-limited” (for example).
I informally proposed “recordedStatus” (yes/no) as a term or category for the operational result found/not found, recorded/not recorded. Logically and in other ways this is NOT the same as present/absent, because absence of evidence is not evidence of absence. I wouldn’t object to an alternative term to “recordedStatus”, so long as it means the same.