FIELD P 

 Columns 50 and 51 



General Use 



Coding in Field P may be considered as one component of a group of three which, together, 

 express the amount of test compound administered: The dosage size (Fields M and N), the frequency 

 of administration of that dose (Field O), and the length of time the test compound is administered 

 (Field P), at that dosage size and frequency. 



Superimposed on this use of Field P is a second use, for the situation in which a secondary 

 compound is administered in a test. In such a test, the test compound is usually administered only 

 once and therefore a field is not frequently needed for expressing duration of treatment. Thus, under 

 these circumstances, Field P is ordinarily free for this second use, the coding of the time between 

 administration of the test compound and the secondary compound. 



Specific Directions and Explanations 



1. Selection of the scale to be used for coding duration of administration 



The purpose in dividing total time into the several scales is explained in the section discussing 

 organization of Field P. The coder will understand that the selection of a scale is left to his judgment. 

 The scale should be used which seems the most reasonable choice relative to the field of chemical- 

 biological research to which the test data belong, i. e. , the scale that will allow the most exact coding 

 of all data from that testing field. This is not always easy. Whether there is always only one scale 

 most appropriate for any one situation might be questioned. It is probably more accurate to consider 

 that for each testing situation certain scales of Field P are more appropriate than others, rather than 

 to suggest that for every situation there is one most appropriate scale. Testing of compounds for 

 molluscacidal activity or for antimalarial activity represents fields of chemical-biological testing for 

 which Scales 1, 2, 3, and 4 might be easily seen to be inappropriate, since such treatment is ordinarily 

 much longer than any of the periods in those scales, so a higher scale would be considered, probably 

 Scale 7, though under some conditions Scale 6 or Scale 8 might be used for molluscacidal or antimalarial 

 data. 



In summary, an appropriate scale in Field P is: 



(1) the scale that allows the most accurate statement of the duration of treatment and-- 



(2) the scale whose time values might reasonably be expected to encompass all durations 



of treatment typically used in testing in the field of chemical- biological research involved. 



To illustrate the first of the above points, consider that to code a 6-minute duration of treatment, 

 Scale 2 would not be the appropriate scale, because it could only be coded as being more than five 

 minutes, which could be 6 minutes or 6 years. Scales 3 or 4 would be more appropriate scales for coding 

 most accurately 6 minutes. To illustrate the second of the points, consider the observations made 

 relative to antimalarial and molluscacidal tests in the paragraph above. 



If the coder has little basis for judging appropriateness of a scale relative to the type of activity 

 for which the test was run, the scale should be chosen on which the observed time falls on (or as near 

 as possible to) the mid-point (Symbol 5 in Column 51). For example, if the duration of administration 

 is 14 days and there is no other basis for selecting another scale, Scale 8 would be selected only 

 because 14 days falls at the mid- point of the scale. In making a selection on this basis, another prob- 

 lem is sometimes encountered as illustrated by a time value of 7 days. In this case, the value is not 

 at the mid-point of any scale and the question arises as to which scale to choose, Scale 7 or Scale 8, 

 since 7 days is as near the mid-point of one as it is the other. In this case, when the scale is being 

 selected only on the basis of proximity to the mid-point of a scale, the CBCC always uses the lower 

 scale (in this case, Scale 7). 



When data are reported in terms such as "several hours" (or as other comparably indefinite 

 expressions of time periods), Scale A should be used. 



100 



