Quite often authors make some claims with some "to the best of our knowledge" disclaimer.
Example:
"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.