How does the leaderboard calculate top observers?

I couldn’t find any explanation of this in the help topics, so apologies if I just missed it!

I am part of and am looking at the leaderboards there.

When I click on the word “species” beside the number for each of the top species observers in the leaderboard, the number returned at the top of the list doesn’t match the one shown on the leaderboard. I also tried doing a worldwide search for observations made in June for high-rank Species for each of the observers on the list, and that returns yet another number.

For example, user carl-adam, currently listed at #4, is shown with 229 species on the leaderboard, 227 species when I click the word “species” for the list, 224 species when I do a worldwide search with high-rank Species, and 232 with no high taxon rank specified.

I am curious about the answer because a map search on my own high-rank-Species observations says I’ve observed 246 species in June (I felt it had to be up there, with my mothing!), so I was surprised not to be on the list. I’m not asking because I’m itching to be included necessarily, but was wondering why I wasn’t if I had similar numbers.

Thanks in advance for any insight! This has me puzzled. :)

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From what I understand, lists are the most buggy part of the iNat interface.

Also, when you think about it, lists are constantly changing, not only by having species added, but also by having species corrected, and sometimes by having species removed when an ID is corrected.


@seabrookeleckie Thank you for bringing out the Peterson Field Guide to Moths of Northeastern North America along with David Beadle. It’s a beautiful book!

To your question … I’ve found that the lists are buggy as @susanhewitt mentioned. Even when the data has been static for months. Something that should be addressed at some point. When I was able to download my identifications (this stopped working for me all of sudden) these numbers didn’t tie to the website results even when all the parameters were the same.


Including URLs can be helpful to examine particular cases. Here’s a page that goes into detail as to how iNat counts “species” in several parts of the website:


The default way that iNaturalist counts the taxa represented by these observations is called the ‘leaf count’. … An advantage of the leaf count is that distinct taxa that have been observed but haven’t been identified to species are included (e.g. Genus Nothopthalamus ), but it avoids double counting (e.g. Family Salamandridae and Taricha torosa ). A disadvantage of the leaf count is that it can be confusing to explain and is costly to compute. You may notice that the the tab on Your Observations is labeled ‘Species’ even though ‘Taxa’ would be more correct as the count may include non-species ranks (e.g. Genus Nothophthalmus ). We sometimes use the term Species rather than Taxa since its more familiar to novices.


When we display leaderboards of several counts side by side (e.g. the Observers tab on Explore or Projects), it is too computationally difficult to compute the leaf count for each. Here, iNaturalist displays the ‘species count’ which entails rolling up infrataxa and then only counting species.


@susanhewitt Good to know! Thanks. :) I imagine the lists take lots of computer power to generate, with so many users to check. And true about counts always changing, though in theory the list should also change then. :)

@nycbirder I’m pleased you like the book! If this pandemic eases, I might even get the last one done. :sweat_smile: It’s funny that the lists don’t match when accessed from different points - you’d think they’d be run using the same search parameters.

@bouteloua That’s helpful information, thank you! I suppose having an organization system where not all labels are equal makes for many programming challenges.


Just want to emphasize that sharing specific examples like URLs and screenshots makes it much easier for others to understand exactly what you’re referring to. There are multiple places that “leaderboards” can refer to.

Ah! I didn’t know that; thanks. I was referring to the six top-5 lists displayed at

I see my name is on the board when I loaded it just now; despite it saying “Updated daily (less than 1 minute ago)”, perhaps the calculations are only run once and when I saw it yesterday it had already run before I’d added my observations for the day.

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yeah, i think the main problem on that screen is the “(less than 1 minute ago)” indicator. if it was fixed to actually display the time since the last pull of the data, or if it was removed altogether, keeping just the “Updated daily” part, then it would be fine. looking at the code, i think right now it’s basically just reporting the difference between now and now, which is no difference, or less than 1 minute ago.


I am interested in how iNat calculated the leaderboard for Shope Papilloma Virus, because I think I should NOT be the top identifier for that taxon.

There is currently only one observation of this species on iNaturalist. I was the 3rd identifier on that observation, and my ID wasn’t even leading (it was already RG).

I get that I’m only on the leaderboard at all because there are only 3 IDs; what I don’t understand why I am the top identifier. Shouldn’t the 2 IDs before mine, which were leading & RG, be somehow weighted to be higher than mine on the leaderboard?

Also, I noticed the leaderboard seems to completely exclude the observer’s ID (which was both the 1st ID and the leading ID):

Is that by design or a bug?


And now there’s a second observation by the same user, and once again the observer is not on the leaderboard at all even though they sumbitted IDs.

But it looks like that is a design choice:

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