Editor,—As I understand the Scientific Method, a statement purporting to be factual, either in a scientific article or in a discussion with peers, must be supported by cited evidence that may be publicly examined for its scientific veracity.

The paper by Heeley et al 1provides data to illustrate the equivalence of conductivity and chloride in cystic fibrosis (CF) diagnosis, and therefore corroborates the findings of an earlier clinical trial by Hammondet al.2 Further, a statistical comparison of the extensive published sweat chloride data of Shwachmanet al with the conductivity data of Hammond shows that the two are …