530 



SCIENCE 



[N. S. Vol. XL. No. 1032 



tion took place in something less than that 

 time. 



The favorite diet of the animals under ob- 

 servation was, without question, freshly killed 

 mice. Shull, estimating four of these shrews 

 to the acre, figured that on a farm of one hun- 

 dred acres, they would, in a year, devour 38,- 

 400. Eealizing the vast amount of damage 

 these rodents are capable of producing in agri- 

 culture and considering also the almost exclu- 

 sively carnivorous habits of the Blarina hre- 

 vicauda, one must admit a great economic 

 value for this shrew. H. L. Babcock 



Dedham, Mass. 



the limit of uniformity in the grading of 

 college students by different teachers^ 

 In the University of Missouri our grades 

 have, since five years ago, been defined by the 

 frequencies of their permitted occurrence: 

 according to our definitions 25 per cent, are 

 superior, 50 per cent, medium and 25 per cent, 

 inferior grades.^ We hoped thereby to dimin- 

 ish or even exterminate the divergence of 

 marking then existing. We actually reduced 

 this divergence; but only two thirds. We 

 failed to exterminate it. One third of the 

 former lack of uniformity persists, as may be 

 seen from my previous report in Science, and 

 we ask the question : Why does it persist ? 



It seems that the chief cause is the inability 

 (call it unwillingness, if you wish, but nothing 

 is gained by any name) of the teachers to 

 differentiate between the performances justly 

 to be expected of a freshman and a senior. 

 For simplicity's sake I speak of two college 

 classes only. Instead of recognizing the rela- 

 tively superior work of certain freshmen 

 among the freshmen, the teacher compares 

 their work with the work of seniors, and then, 

 of course, finds it to be but weak. And, in- 



1 Eead before Section L — Education — American 

 Association for the Advancement of Science, At- 

 lanta, December, 1913. 



- Compare two former papers : ' ' The Grading 

 of Students," Science, 28, pp. 243-250, 1908; 

 ' ' Experiences with the Grading System of the Uni- 

 versity of Missouri," Science, 33, pp. 661-667, 

 1911. 



stead of recognizing that some of the seniors 

 are much less accomplished than other seniors, 

 the teacher compares the weaker senior's ac- 

 complishment with that of the freshman and 

 finds it quite remarkable. The result is a 

 widely spread tendency of teachers to report 

 an excess of inferior grades in freshman classes 

 and an excess of superior grades in senior classes. 

 This seems to explain that persistent fraction 

 of the lack of uniformity which we could 

 not eradicate. 



Here is the example of an individual teacher 

 in history whose total distribution of grades 

 is approximately that prescribed by the uni- 

 versity : 



25^ Sup. 50? M. 'Jo-Miif. 



Underclassmen 1 



Upperclassmen 6 



Is there any remedy? It seems simple. Let 

 the teacher differentiate more between the work 

 of freshmen and that of seniors. Assign to 

 the freshman such tasks as are appropriate to 

 the condition of the student who has just left 

 the high school, and to the senior tasks which 

 approach in difficulty, in the requirement of 

 initiative, of resourcefulness, the tasks which 

 the research work of the graduate school keeps 

 ready for the senior as soon as he has his 

 diploma. 



But this remedy is not as simple and easy 

 of application as it looks, for the average 

 college teacher seems to be incapable of mak- 

 ing the differentiation required. Instead of 

 comparing, rather, freshmen with high-school 

 pupils and seniors with graduate students, he 

 compares freshmen with seniors in the per- 

 formance of an identical task given to both. 

 However, we must have patience with the 

 teacher. His own task is not small. There 

 are three influences from which he can not 

 easily free himself. (1) Freshmen and seniors, 

 after aU, belong socially to one group, that of 

 college students, and neither to the group of 

 high school pupils nor to that of members of 

 the graduate school. (2) He is in mental 

 contact with both freshmen and seniors all 

 the time, but usually no longer with high 

 school pupils and not, probably, with graduate 



