Ah ok.. I really thought I had seen something like this been mentioned before.. but maybe that was just wishful thinking actually
Ajott, a simple approximation, but maybe this is good enough.
If you go to the Explore page and set the Needs ID filter, it show over 85 million observations, the vast majority of which have only one ID. Is there a reason you need to exclude those with multiple (conflicting or supraspecific) IDs?
If one primarily IDs taxa that often can’t be ID’d to species from photos (e.g., spiders, ajott’s speciality) and IDers only infrequently use the “ID cannot be improved” button to make them RG at genus, it can be difficult to determine which observations have already been looked at by someone and which have not. If the volume of observations is such that reviewing everything in the taxon would be impractical, I imagine that sorting for observations with only one ID would be a reasonably good way to prioritize those which have gotten the least amount of attention.
I sort by date observed, then dig from the bottom of the heap.
Quite a lot has been missed, ignored, forgotten, trapped between 2 opposing factions - of which one side was enthusiastic newbies who have moved on to the next Shiny NEW, or taxonomy orphans.
@spiphany Gave a good explanation. When I go through larger subsets (like in the moment Tigrosa needs ID) I like to shake it up regularly to make it more interesting for me - all Tigrosas starting with the most recent or the oldest or in random order, only certain species, only obserations stuck at genus level, only in certain regions… generally it feels most rewarding helping observations that have been ignored so far or resolving disagreements.
For higher order taxa level I have some workarounds.. e.g filtering for RTA clade or entelegynae will almost always show me observations with disagreeing IDs.. filtering for Araneae shows a lot of ignored observations…
but ya well, if it is not possible it is how it is.
btw. “only” 25.000 to go 
CNC is only a week away, and nobody has brought this thread forward?
I must admit that I may not be meeting the challenge posed in the OP (doing five more identifications than average, each Friday), but that’s only because I’m already spending far more time on iNat than I really ought to. But I do look forward to this thread every week, as a form of mutual encouragement for the identifier community.
So, besides dealing with my share of the spring wildflower observations that are pouring in, five weeks ago I mentioned my project for reviewing the “Needs ID” pile or Arisaema observations. I started with the most recent observations and I’ve been working my way back through time. It might be appropriate that I’ve now reached the observations from last year’s CNC. Meanwhile, new observations have been posted that I haven’t been looking at, and next week we’ll have another CNC.
Oh boy!
Oh, boy, indeed! While the spring increase in observations started around here about a month, it has really ramped up in the last day or two. It feels as though I refresh and ID, refresh and ID, refresh and ID, and I never catch up. Actually, it’s rather enjoyable, I must admit.
And the CNC starts a week from today. I wish you all strength and enjoyment in your identifying, and I hope you get out yourself to make lots of observations.
The weather forecast is predicting showers for only one out of the four days. And temperatures will be pretty reasonable, too! 
My New Mexico “Not Expected Nearby” list is below 2700 unreviewed. Garden plants will be marked!
Have worked thru the beautiful moraeas for a researcher.
Back to 2.5K proteas … but will probably have to start again with fresh residue after CNC.
Once the CNC starts?
There is a Global Projects for iNatters who don’t have a local project.
A good way and place to encourage shiny new iNatters with our IDs. Even a broad ID shows that ‘someone has seen my obs’.
https://www.inaturalist.org/projects/city-nature-challenge-2025-global-project
How to do the CNC?
Are you asking how to participate as an identifier in the CNC? If so, the answer is to make as many IDs as you can before the end of the six-day ID period that follows directly after the four-day bioblitz itself. So that means as many as possible before the end of Sunday, May 4th, your time. (ETA: Observations can be IDed afterwards, of course, but they don’t “count” for the CNC results.)
There are different philosophies/methods/whatever people follow to make IDs for the CNC. You can work to get as many observations as possible to Research Grade. Or you can mark as many captive or cultivated organisms Not Wild as you can; so many observers for the CNC are brand-new to iNat and don’t know they should concentrate on wild organisms (and if they are students, their teachers don’t emphasize that point enough). New observers also upload many observations without any ID, so you could go through Unknowns and give them as best of an ID as you can. It’s probably best to work through your own region first, since you likely know those organisms best, and then if you still have time and energy (ha!), you can branch out to other regions.
Or are you asking how to participate as an observer in the CNC?
Perfect, thank you!
Or you can choose the local project that appeals to you this year - work to ID for them, while the taxon specialists are (still) available, and before the cutoff.
So disappointing to come across good photos of interesting biodiversity - when it is ‘too late’.
https://www.inaturalist.org/projects/city-nature-challenge-2025
Neither the list nor the map are user friendly. Keep scrolling.
It was a good day for iNaturalists today in my region (New England in the US) - good weather, a weekend, spring is finally here, perhaps an Easter dinner to walk off (or maybe relatives to avoid by taking a walk?). I was working through Needs ID observations here and wondered just how many had been submitted today.
The answer is 3,885 so far (six hours to go in the day). Of those, 1,171 are already Research Grade (!!) and only 120 are Unknowns. For a non-CNC day, that seems like a lot of observations.
With the CNC approaching, I have 1,800 unreviewed Unknowns and 2,400 unreviewed “Not Expected Nearby” in New Mexico. Will they double by this time next week?
I’d bet they will more than double. Although, in New England, I have about 9,000 unreviewed Unknowns currently and I really, really hope they don’t double by next Monday at midnight.
I cannot … I will use my bookmarked URLs for accounts less than a week old to catch the newbies.
The ‘residue’ must wait till the dust has settled. Then we start again … till Great Southern Bioblitz for me.
One way I found is to use the “identifications” page with the category=leading parameter. That should only give you observations with single IDs or with unresolved disagreements. I don’t know if there is an easy way to get the set of observations displayed there into “identify”. If so, that may be a work-around.