474 KEPORT— 1889. 



On tlie Principle and Methods of assigning Maries for Bodily Efficiency. By 



Francis Galton, F.B.S. 



The principle and methods by wliicli marks in examinations can 

 justly be assigned is of no small interest to anthropologists, on account 

 of their bearing on the art of describing the various degrees of human 

 faculty among individuals and races. What will now be said is of 

 general application, though it is written especially with reference to 

 examinations in physical powers. 



The question to be solved is of this kind. Suppose that one man 

 can just distinguish a minute test object at the distance of 25 inches, 

 another at that of 35, and again another at 45 inches, how should we 

 mark them ? We should be very rash if we marked them in the pro- 

 portion of 25, 35, and 45, or even if, tor some good reason, we had selected 

 25 as the lowest limit from which marks should begin to count, we 

 should mark them as 0, 10, and 20. 



Two separate considerations are concerned in the just determination 

 of a scale of marks, namely, absolute jjerformance and relative rank, 

 which are apt to be confused in unknown and varying proportions. 



Absolute performance is such as is expressed by the 25, 35, and 45 inches 

 just spoken of. It is perfectly correct in some cases to mark, or let us 

 say to pay, for this and this alone, upon the principle of piece-work, 

 namely, that the pay ought to be proportionate to the work accomplished, 

 or to the expected output in after life. 



Relative rank is, however, on the whole, a more important considera- 

 tion than the absolute amount of performance by which that rank is 

 obtained. It has an importance of its own, because the conditions of 

 life are those of continual competition, in which the man who is relatively 

 strong will always achieve success, while the relatively weak will fail. 

 The absolute diSerence between their powers matters little. The strongest 

 even by a trifle will win the prize as completely as if he had been strongest 

 by a large excess. Undertakings where many have failed are accomplished 

 at last by one who usually is very little superior to his predecessors, 

 but it is to just that small increment of absolute superiority that his 

 success is due. Therefore it is clear that relative rank has at least as 

 strong a claim for recognition as absolate performance, if not a much 

 stronger one. They have each to be taken into separate consideration, 

 and each to be separately marked. The precise meaning intended to 

 be conveyed by the phrase ' relative rank ' will be better understood 

 further on. 



Recurring to the example of keenness of eyesight, let the test object 

 be words printed in diamond type, and the persons tested be Englishmen 

 of the middle-classes, between the ages of 23-26, then the performance of 

 reading diamond type at 25 inches happens to be strictly mediocre. Fifty 

 per cent, of the many persons who were tested performed better than 

 this, and fifty per cent, performed worse. The 35-inch performance was 

 exceeded by only 2^ per cent, of the persons tested, and as to the 45-inch 

 performance it has not in my experience been reached at all. I have had 

 12,000 persons altogether tested in this way, of both sexes and of various 

 ages, but not one of them has succeeded in reading diamond type at the 

 distance of 45 inches. It is very rare to find one who can do so at 40 

 inches. Wherever superiority in eyesight is eminently desirable, it would 



