FIELDS W, X. and Y 



Columns 68; 69 and 



70; and 71 



curve) are caused by larger doses (a shallower curve, Symbol #) or by smaller doses (a steeper curve, 

 Symbol *), than would be indicated If the curve were exactly parallel to the fixed lines of the Grid , 

 or whether responses in less than 50% of the individuals are caused by smaller doses (a shallower 

 curve, Symbol #) or by larger doses (a steeper curve, Symbol *). 



As indicated above, when any curve plotted on the Grid deviates from the slope of the fixed 

 reference lines of the Grid, the CBCC uses always the evaluation indicated by the point at which the 

 curve of the data crosses the mid-line (the 50% -of-individuals-responding level) of the Grid. If the 

 testing has not been pursued to that point, the curve fragment which can be plotted on the Grid from 

 the data given can ordinarily be extended by interpolation to the mid-line (the 50% level) to determine 

 the appropriate Grid area from which the evaluation symbol should be taken. For example, if the 

 compound has not been administered in sufficient quantity to cause 50% of the individuals to respond 

 or if time values (durations of response, e. g. ) have been expressed only in terms of the values for 

 more than 50% of the individuals tested (e.g. , durations of response in 100%, 75%, and 60% of 

 individuals, but not the percentage of individuals in which the response may have endured longer), 

 the curve plotted on the Grid would not reach the 50% level, in which case interpolation is indicated 

 as the appropriate procedure for determining an evaluation. When the curve deviates to the extent of 

 falling into two or more areas of the Grid, Field Y evaluation is derived from the area in which the 

 curve, or interpolated curve, crosses the 50% line. 



Whenever the above situation exists in which the plotted curve extends into two or more Grid 

 areas (and the area in which the curve crosses the mid-line is used as the evaluation indicator), the 

 CBCC always codes the field from which have been derived the abscissa values (quantitative dosage 

 or duration of administration values, Fields M, N, or P , or special time values, Field U) to correspond 

 to the evaluation expressed in Field Y . In other words, after plotting the curve and after coding Field 

 Y with the value indicated by the area of the Grid in which the curve crosses the mid-line, the coder 

 should study the fragment of the curve that lies wholly within that area of the Grid indicated thereby 

 in Field Y. The extremities of that fragment should determine the coding in Fields M, N, or P 

 (Criteria 51, 52, or 53) or Field U (Criteria 54, 57, 58, or 59). At the upper and lower points where 

 the curve leaves that Grid area, the abscissa should be read (i. e. , the bottom, horizontal scale of 

 the Grid- -the dosage/time value scale) and these two readings should determine the coding in Field M, 

 N, P, or U, whichever is applicable in the case. If that entire range of doses (or time values) is 

 included in a single code range of the field in question (M, N, P, or U), that field can be coded with 

 a single code symbol; however, if that entire range of doses (or time values) falls in two or more code 

 ranges of Field M, N, P, or U, that field must be double coded to indicate the range over which the 

 Grid evaluation (Field Y) is applicable. The two symbols, * and #, in Field Y indicate that doses (or 

 time values) greater than (or less than) those coded would cause smaller (or greater) percentage 

 response than the evaluation coded in Field Y would indicate. 



The following are special observations and directions concerning the use of the Grid, organized 

 as a list of numbered items merely for convenience in reference. 



1. For a given dose of test compound (or for a given duration of response, e. g. ), the percentage 

 of Individuals responding may be reported as a range of response . In this case, code the average of 

 the extremes of the range. For example: "A 5 x 10-2 m concentration of the test compound decreased 

 infestation 30-80%". Here, the CBCC would plot the dose vs. 55% (the average of the range of the 

 percentage of individuals responding), for a single point on the Grid. 



2. When a single point is plotted on the Grid (e. g. , a single dose administered vs. the percent 

 of individuals responding to that dose) and when it falls exactly on one of the fixed reference lines of 

 the Grid, there is a question of selecting the Grid area to the right or the area to the left of that line 

 for the Field Y evaluation. The CBCC has established the rule of always coding the lower value (i. e. , 

 the Grid area to the right of the plotted point), for consistency. 



3. When the test has demonstrated only that 100% of the individuals tested respond to the lowest 

 dose administered, there is no assurance that a lower dose, if tested, would not have caused the same 

 intensity of response in 100% of the individuals. The superiority of having determined the minimum 

 dose causing a maximum response of which the test compound is capable Is discussed in the section 

 on General Use of Fields W, X, and Y, in explaining the uses of Field W. The Grid can not be used for 

 this data, but only Criterion 62 (or 01) with Symbol M or N in Field W. 



208 - 



