UNITED STATES DEPARTMENT OF AGRICULTURE 
1 BULLETIN No. 529 
•to 
Contribution from the Office of Farm Management. ^Lg 
S&f'^TU W. J. SPILLMAN, Chief. nS&7* < &WU 
Washington, D. C. 
PROFESSIONAL PAPER 
April 5, 1917 
VALIDITY OF THE SURVEY METHOD OF 
RESEARCH. 
By W. J. Spillman, Cliief, Office of Farm Management. 
CONTENTS. 
Introduction 1 
How farm records are obtained ' 2 
Accuracy of the farmer's knowledge 7 
Page. 
Accuracy of cost-accounting methods 8 
Law of error 9 
Mistaken notions of accuracy 13 
INTRODUCTION. 
The distinguishing feature of farm-management investigations is 
the application of the inductive method of reasoning to farm prac- 
tice. In practically all farming communities can be found examples 
of successful and of unsuccessful farms. It is assumed that a careful 
analysis of the methods and business system of a large number of 
farmers, all working under essentially similar soil, climatic, and 
economic conditions, may be made to reveal the reasons for the suc- 
cess of one and the failure of another. The essential difference 
between the farm-management method and the laboratory method 
of investigation lies in the fact that the laboratory investigator varies 
his causes and studies the resulting variation in the effects produced. 
The farm-management investigator has his experimental results 
already produced for him. He merely collects the results of farm 
experience, arranges them in such manner as to display the varia- 
tions of a causal factor, and then studies the resulting variations in 
the effects produced. Suppose, for example, it is desired to know 
what degree of soil fertility will result in the greatest profit to the 
farmer under the conditions prevailing in a given locality. Having 
analyzed the business of a large number of farms in the locality, the 
farms are first grouped on the basis of their yields per acre, with 
enough farms in each group to give reliable averages. The average 
profit made by the farms in each group is then determined. Table I 
77589°— 17 
