VALIDITY OF THE SURVEY METHOD OF RESEARCH. 7 
from memory. The record from the manager gave a labor income of 
$3,688, that from the overseer $3,656, a difference of $32, which is 
less than 1 per cent of the quantity involved. It should be remem- 
bered that records of this kind are used only in averages, so that 
errors in them are for the most part eliminated by the law of aver- 
ages. (See p. 9.) 
ACCURACY OF THE FARMER'S KNOWLEDGE. 
The opinion prevails quite widely, even among farmers them- 
selves, that the average farmer knows very little of the details of his 
business. The results given in the foregoing pages indicate that this 
opinion is not consistent with facts. During the past decade the 
Office of Farm Management has analyzed the business of nearly 
20,000 farms. The experience gained in this work indicates that the 
average farmer does know the details of his business with a fair 
degree of accuracy, the discrepancy in his knowledge being relatively 
small in the case of the larger and more important items, but in- 
creasing as the importance of the items decreases. One reason for 
this is the fact that in a year's business on the average farm there 
are relatively few business transactions, most of them being fairly 
large items. The principal product of the farm is, in many cases, 
disposed of in a single sale, and the farmer remembers the details of 
this sale quite accurately until the corresponding figures for a new 
year replace them in his mind. In many other cases a product, such 
as eggs, milk;, etc., is sold in fairly regular quantities from month to 
month, and the farmer remembers with a fair degree of accuracy the 
usual monthly income from such sales, as well as the variations in 
this income. 
But though the farmer does know fairly well the details of his 
business, he is not always aware of this fact ; and it requires no slight 
skill on the part of the investigator to reduce his questions to the 
terms in which the farmer carries the information in his head. Un- 
less this is done, the answers given by the farmer are mere guesses 
and are of small value. Thus, if we ask a farmer how much profit 
he made on a certain field of corn he will usually not even hazard a 
guess at the answer, because he realizes he does not know ; but if we 
analyze the cost and income from this field into its elements we find 
the farmer has very definite knoAvledge of these elements. He knows 
the operations, such as plowing, harrowing, planting, etc., done in 
raising the crop. He knows the amount and value of the fertilizers 
applied. He knows how much corn was secured and its market value. 
The trouble is not that the farmer does not know the facts necessary 
to arrive at the profit made from the field, for he does know them ; 
but he does not know how to use these facts in calculating the profit, 
because his knowledge of cost accounting methods is meager. The 
