Document B8bdrG6wn25x1wkRdzVqkB79X

-J Am e r i c a n Pe t r o l e u m In s t i t u t e V.C. BUfiftUCHS CONSULTANT . 1271 AVENUE OF THE A M ERI CA S N e w Y o r k 20. N. Y. April 19 , 1962 Dr. John H. Ludwig, Chief Laboratori?- of Engineering and Physical Sciences Robert A. Taft Sanitary Engineering Center 4676 Columbia Parkway Cincinnati 26, Ohio . O FFI CERS M . J. RA T H BO N E, c m a i a m a n o r 00**0 F R A N K M . P O R T E R , PCSO EN T V . A . O E L L M A N . V I CE PA CSi O f i N T A . P . F R A M E . V i c e PRESI D EN T G A G E L l l N D . v i c e PRESI D EN T A . O . SA V A G E . V I C E PPCSl O EN T H E N D E R SO N SU P P L E S. JR . . V*CC PA C & i O Es P . C . SP E N C E R . T REA SU RER W I L L A R D M . W I L SO N . SC C n t T A H Y Dear John: With regard to Hofreuter, et ai, report on the bloodlead studies in Philadelphia, my comments would closely follow those outlined in Don Diggs' letter of April 13* 1962. In addition, I should like to comment that the reader is likely to become confused by the intermingling of what is significant from mathematical treatment and health standpoints. The opening statement that the "investigations be under taken to evaluate the public health significance" is followed by an extended analysis of statistical significance. There is a sentence on the first page and a sentence on the last page Indicating that the difference in the blood lead concentrations of the various groups studied do not have health significance. C\ ? C\> S- o o o kt In a mathematical sense the word "significant" is de fined and has meaning. Outside this field the bare word "sig nificant" is vague and implies Importance without stating why or how important. In my opinion more accurate and'descriptive terms should be used in scientific writing to define the degree of importance of a finding. The expression "is significant because" would, of course, be acceptable. The material in the report could easily be reorganized to avoid misunderstanding on the part of the reader. Yours sincerely, LCB:rp . cc: V. H. Castrop D. R. Diggst K. Hesselberg R. A. Kehoe ' J. A. Maga 4 C. L. Samuelson^ R. 0. MeCaldina