As mentioned earlier, you can verify this yourself; otherwise, you would subject any other source to doubt, necessitating further verification.
Two months ago, OSINT Archi Irving took the time to check Oryx for duplicates (yes, all 15,554 records from both sides), and he posted the results.
For Russia, out of 11,487 records, 136 duplicates were found (1.2%). For Ukraine, out of 4,067 records, there were 114 duplicates (2.8%).
In total, out of 15,554 records, there were 2% duplicates if rounded.
When Archi finds duplicates, he sends them to Oryx, and they remove them from the lists. That's why you might sometimes see on the website that there were, for example, 11,490 losses, but it became 11,487.
Two conclusions:
- Duplicates among Ukrainian losses occur twice as often as among Russian losses. This is related to the "one 'Leopard' or 'Bradley' from 30 different angles" effect from Russian "war correspondents."
- The overall margin of error at 2% is exceedingly small - the documented Oryx losses are highly reliable.