If you are unaware, there are two sets of test methods that are currently in use for many of the common tests that we see reported on data sheets and certificates of analysis. This has caused a lot of confusion.
To add to the confusion, I have seen many data sheets and certificates of analysis in which data is reported incorrectly. None more than izod impact. There is currently an ASTM method and an ISO method for testing izod impact. Although some data sheets claim that they are, the two test methods used for izod impact are definitely not equivalent. They are two different test methods and there is no way of converting between the two.