Changes to 5. Basis for Precision Statement are meant to improve clarity. 5.1 was reworded to clarify the role of laboratories in generating data and other changes are meant to improve readability. Changes in 5.4 removes a confusing phrase “as a minimum” and breaks up a long sentence into separate sentences. Also the addition of the statement about difference limits not being included makes it agree with language used in X1.7. The change in 5.6 is meant to emphasize inclusion of known potential sources variation.