176 NATURE-STUDY REVIEW [6:6-Sept..i9io 



efficiency of the teaching. Certain factors are already fairly well 

 established from the investigations already undertaken. In 

 connection with arithmetical abilities, for example, it is clear, 

 both from Stone's results and from Rice's earlier work (see 

 Forum, 1902), that home environment is a factor of far less im- 

 portance in determining such abilities than the average teacher 

 supposes. Whether this holds for other types of ability 

 (for other conduct-controls) is still to be determined, but one 

 thing is pretty definitely established: generally inadequate re- 

 sults in arithmetic are not to be attributed to the operation of 

 out-of-school factors. 



In connection with the parallel-group method, the objec- 

 tion is frequently raised that the bias of the teacher is an all- 

 important factor, and that the results will be valid only for the 

 teacher who conducts the experiment. In how far the "personal 

 equation" can be eliminated in this type of research is a ques- 

 tion that is to be determined only by repeated tests of the 

 method, and even if such repeated tests show undoubtedly that 

 "results" are entirely independent of any factor save the teach- 

 er's enthusiasm, it will simply mean that organization of subject- 

 matter and method of teaching are topics that need not concern 

 us further. This will be a valuable result if it is established, for 

 it should put an instant stop to the controversies over subject- 

 matter and method that rage so violently in every educational 

 camp. It is hardly probable, however, that, if personal bias and 

 prejudice can be eliminated in every other form of scientific 

 inquiry, educational research will form so conspicuous an excep- 

 tion to the general rule. It will be recalled that the same ob- 

 jection was voiced when psychology adopted the experimental 

 method of research, and yet the results of experimental psychol- 

 ogy stand today as a substantial answer to the criticism. But 

 the criticism has its value in pointing to the danger of applying 

 the experimental method ad lihHum and without due refer- 

 ence to the ever-present need of the scientific attitude. Inves- 

 tigations of this type should be most carefully scrutinized, and 

 every possible source of error pointed out. Indeed, not the 

 least valuable result of such program as is here indicated will be 

 the inevitable discovery of factors that have hitherto escaped 

 attention. 



Finally to those who object to the scientific investigation 

 of educational problems on the ground that such investigation 



