Currently for identifications, there’s the concept of a branch disagreement. This can occur when you identify an observation as a taxon that is an ancestor of the observation’s current taxon and then click a box to indicate that there’s not enough evidence to identify at the lower observation taxon. Your branch disagreement identification would effectively disagree with any descendant taxon to your identification taxon.
For example, suppose you came across an observation with just one identification for species Rudbeckia amplexicaulis, and you made a branch disagreement identification for genus Rudbeckia. Then the observation’s taxon would change from species to genus.
There has been occasional intense discussion about how branch disagreements are / should be initiated (ex. https://forum.inaturalist.org/t/change-wording-used-by-the-system-when-downgrading-an-observation-to-an-higher-level-taxa/3862). Part of the discussion led to talk of changes to clarify branch disagreements and to provide a new type of “leading disagreement”. But more than 2 years since that talk, no changes have been deployed to the masses, and I assume that means that there were issues discovered when alpha testing this functionality that may have halted the progress of that effort.
There’s also the “Can the Community Taxon be Improved?” DQA item in the Data Quality Assessment section of an observation:
I think the “Can be Improved?” item is intended to provide a mechanism to prevent hard-to-identify-to-species observations from lingering indefinitely in the Needs ID pool. For example, clicking “No, it’s as good as it can be” on the earlier Rudbeckia observation example would go ahead and make the observation Research Grade at the genus level. Alternatively, it could take an observation identified to family and put it in the Casual pool if it’s unlikely that anyone will be able to identify it to a lower level.
Unfortunately, because the “Can be Improved?” DQA item operates at the observation level and works on a yes / no voting model, it can sometimes lead to unexpected / undesired behavior:
I think the way to improve the situation for both branch disagreements and “Can be improved?” is to eliminate the observation-level “Can be Improved?” DQA item in favor of an identification-level “Cannot be Improved” flag.
When a user goes to make an identification, there could be an extra little checkbox (or something like that) to the right of the taxon selection that the identifier could check if they want to indicate that they don’t think it’s possible (for anyone) to identify to a lower level:
If the flag is checked, the identification could display an extra little “Cannot be Improved” indicator. (If it triggers a branch disagreement at that point, then the disagreement would also be indicated separately, as it currently is.)
This way, identifiers would be able to record that they don’t think the observation can be identified to a lower level without having to wait for a lower-level taxon to explicitly disagree with. (Checking the flag would provide an implicit disagreement with descendant taxa, regardless of whether the other IDs were recorded before or after.)
Then you could also piggyback on the main identification voting system to determine whether a higher-than-species community ID can be improved (should remain Needs ID or not). If >2/3 of identifiers believe that the identification cannot be improved beyond a particular higher-than-species taxon and rank, then that will trigger genus-level observations to go to Research Grade and higher-level observations to go to casual. Otherwise, the observation remains at Needs ID.
(I think this simplifies things conceptually here since you don’t have to consider a separate yes / no vote on the DQA item, but some might perceive that requiring >1 person to trigger the cannot-be-improved action might be a bad thing though.)
Besides the obvious required data model changes to support this proposed change, there would be a big question of how to handle data conversion. I think at the very least, you would treat existing identifications that are branch disagreements as having the new ID-level “Cannot be Improved” flag. Then, if it makes sense (I’m not sure it does), you might consider marking the IDs for folks who have indicated “Can be Improved?” = No as having their IDs also get the “Cannot be Improved” flag. Also, if it makes sense (I’m not sure it does), you might also consider making any subsequent identifications at the same level as a branch disagreement identification get the “Cannot be Improved” flag, too.
Since there’s not a perfect way to accomplish an exact data conversion, you would end up with many higher-than-species-level observations going back to the Needs ID queue.
What I’m describing here does not address the previously proposed “leading disagreements” functionality explicitly, but it might lay the groundwork for alternative (more elegant) ways to implement leading disagreements.