400 
APPENDIX 
confusion, a method of rating which applies equally well to all 
tests was devised. 
This method starts by taking the perfect completion of a 
certain number of units in a certain time as a point of reference. 
For instance, in test number 2, sorting the 50 cards perfectly 
in 35 seconds is taken as the point of reference. Then, 35 sec 
onds divided by whatever time the individual takes will be 
the rating for the individual. For instance, an individual who 
does the test in 35 seconds will be rated 35 -5- 35 or 1.00. One 
who does it in 40 seconds will have 35 -f- 40 or .87. If anybody 
does it in 30 seconds the rating will be 35 -5- 30 or 1.20. This 
is higher than 1.00. However, by selecting as our reference 
time a record in the test which only the very best individuals 
can reach, the subsequent ratings will approach, but seldom 
pass 1.00. 
In many tests, however, every subject is allowed only a cer 
tain length of time. Therefore, since the time is always the 
same, it becomes necessary to divide the number of units com 
pleted by the number of units called for by the point of reference 
(RU). E. g., test 8, 120 seconds is the time. The point of 
reference is the completion of 70 numbers in that time. If 
only 60 are completed, the rating in the test is 60 -5- 70 or .86. 
If the 70 are completed, the rating is — or 1.00. 
70 
The next step is to compensate for mistakes. In tests like 
8, where the time is always the same, it is only necessary to 
subtract the number of mistakes from the amount completed 
before dividing. 
E. 
g-> 
Therefore, whenever 
the time limit for a test is uniform, the rating formula is: