FIELD U 

 Columns 65 and 66 



7. Relationship between Field U and Field P (duration of administration of the test compound ) 



When Field U is coded with time to specific action, or "killing time", or "alteration of 

 survival time" (Criterion 10, 11, 12, 57, 58, or 59 of Field X), the coding in Field P should always 

 be consistent with the coding in Field U, in the following respect. A duration of administration coded 

 in Field P should never be longer than a "time to specific action other than death", or a "killing time", 

 or a time of death of the organism whose "survival time has been altered" coded in Field U--even if 

 the test were run by a standard technique in which the administration was routinely over a longer period 

 or if, in the case of making evaluation by "time to specific action other than death", administration 

 had actually continued beyond the beginning of response. This aspect of Field P is discussed in a 

 general way in Division 2 of Specific Directions and Explanations of Field P. 



When Field U is coded with a duration of action (Criterion 13 or 54 of Field X), the administration 

 must have ceased prior to the action, else the action's duration could not be assessed; therefore, when 

 Criterion 13 or 54 is used, Field P is always coded with the actual entire duration of administration. 



8. Relations between Field U and Fields X and Y; use of the code symbols of Field U for evaluation 



While the information coded in Field U is in a sense independently important, just as the infor- 

 mation of any other coding field (the test organism, the dosage, the route of administration, etc. ), it 

 is at the same time so intimately linked with the coded evaluation in Fields X and Y that the two coding 

 areas are often mutually dependent. To summarize: The previous divisions have explained that if 

 Field X is coded with "duration of action" (Criterion 13 or 54), the value coded in Field U can be only 

 duration of action; if Field X is coded with "time to specific action" (Criterion 10 or 58) or "killing 

 time" (Criterion 1 1 or 59), the value coded in Field U can be only time to specific action or killing 

 time (with an exception explained in Division 9); if Field X is coded with "alteration of survival time" 

 (Criterion 12 or 57), Field U can be coded only with alteration of survival time. The significance of 

 this is that the meaning of the entry in Field U is distinguished only by the coding in Field X or the 

 Symbol * in Column 66. Without the appropriate coding in Field X, an entry in Field U is ambiguous. 

 Therefore, if Field X is coded with none of these eight criteria, Field U is ordinarily not coded, with 

 the exception that it may be coded with "persistence of activity of residue", under conditions described 

 in Division 4, or it may be coded with a duration of action, if this is known, as explained in paragraph 

 4 of Division 1. 



When evaluation is by any of Field X Criteria 10, 11, 12, 13, 54, 57, 58, or 59, the code 

 symbols of Field U are used to derive the evaluation symbol to be coded in Field Y. Criteria 10, 11, 

 12, and 13 base evaluation solely and directly on the time value coded in Field U. The coding pro- 

 cedure in these cases is simply to use for Field Y the value coded in Column 66 of Field U--or the 

 reciprocal of that value- -as follows: 



Field X Field Y 



Criterion 10 The reciprocal of the value coded in Column 66 



Criterion 11 The reciprocal of the value coded in Column 66 



Criterion 12 The value coded in Column 66 



Criterion 13 The value coded in Column 66 



Criteria 54, 57, 58, and 59, however, base evaluation not only on the time value coded in 

 Field U, but also on the per cent of organisms responding, from which association there results a 

 value used as a code evaluation in Field Y, as follows: 



- 165 



