Quite often authors make some claims with some "to the best of our knowledge" disclaimer.
"To the best of our knowledge this is the first time this approach has been used to address this problem".
Is there any research/study/survey that tried to look at how often such claims are false? (e.g. some counterexample can be found)
I am mostly interested in the field of machine learning / data mining in English-speaking venues, however any reference on occurrence of such false assertions would be of value.