FIELDS W, X, and Y 



Columns 68; 69 and 



70; and 71 



In addition to Symbols J, K, L, M, N, 0, and P described in the paragraphs above, Field W is 

 used to qualify coding in Field Y by Symbol Q, as explained below in the section of Specific Directions 

 and Explanations, Division 3 and the next to last paragraph of Division 6. 



In the development of the Biology Code, Field W was originally used for another purpose, the 

 coding of the slope of the dosage-response curve, a measure of activity of special importance in insec- 

 ticide studies. As the CBCC program of coding gradually broadened, the need for coding this more special 

 measure, and the use of Field W, diminished to an unrewarding level, corresponding to the lowering per- 

 centage of insecticide data coded. Therefore, Field W was converted to its present use to compensate 

 for deficiencies felt in Fields X and Y, as pointed out in the preceding paragraphs. While Field W is no 

 longer used to code slope of the dosage-response curve, the CBCC has continued to demand its being 

 recorded as part of the written abstract, when it is encountered as part of the data. To indicate, by code, 

 that such a written record exists on the Code Sheet, Symbol * (i. e. , the IBM 12 zone punch) is coded in 

 Field W. Under these circumstances, a brief explanation of this slope of the dosage-response curve is 

 given below. 



With any single, fixed degree of response in the individual organism (e.g. , "maximum" response, 

 or "threshold" response, etc. , or, in the case of toxicity, "death"), tests can be performed on a group 

 of individuals to determine variation between the individuals of that group relative to the dose size 

 needed to produce that intensity of response; in other words, if variation exists, it will be expressed in 

 terms of variation of dose size producing the given intensity of response, some organisms responding at 

 the given intensity with higher doses, some with lower doses. The tests will determine the percentage 

 of organisms responding (at the given intensity of response) at each of the several dose levels. 



By plotting these dosages against the cumulative percent of organisms responding to each re- 

 spective dose (at a given intensity of response), a curve will be described the slope of which depends 

 upon the test compound and which therefore is descriptive of the test compound's action. The slope of 

 this curve is significant in such studies and is expressed by the standard calculation: 



ED 



50 



LD 



50 



(when ED 5Q [or LD 5Q ] 



log ED 



84 



log LD. is equated to 1) 



Thus: 



(The dose causing the given intensity 

 of response in 50% of the individuals 

 tested) 



(The log of the dose causing the given 

 intensity of response in 84% of the 

 individuals) 



log ED g4 - log ED 5Q 



Field W was used only when the above calculation could be made; in other words, only when the 

 test compound proved to kill or cause a non-lethal response in at least 84% of the individuals treated. 

 If less than 84% of individuals respond to the test compound at any dose, the slope could not be expressed 

 in Field W. Otherwise the coding could be visualized as describing curves of any slope up to infinity 

 (infinity implying no variation between individuals, but an all-or-none response or death in 100% of indi- 

 viduals at threshold dose). At the time Field -W was used for this purpose, the 12 zone punch, Symbol *, 

 was used to indicate that the curve was compound, polymodal, or inflected. 



A scale was provided in which calculated slope values were organized into ranges, in the same 

 way that quantitative values of other fields are organized in ranges, and each range was assigned a code 

 symbol. The coding in Field W permitted a discrimination between test compounds whose activity eval- 

 uations indicated by coding in Fields X, Y, and the dosage fields were identical or similar. 



For every code line prepared, both Field X and Field Y must have an entry. A code symbol in 

 Field Y, without an entry in Field X to explain the terms in which that Field Y symbol expresses eval- 

 uation, would be meaningless, as some experience in coding evaluations will demonstrate. Likewise, 

 a code symbol in Field X (stating the criterion on which evaluation is based), without an entry in Field Y 

 (i. e. , omitting the evaluation itself), would be unreasonable. 



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