6 . BULLETIN 529, U. S. DEPARTMENT OF AGRICULTURE. 
these same farmers kept records of the actual days available for such 
work on their farms for a year. Table VI gives a comparison of 
the estimate and the record on each of the 10 farms. 
Table VI. — Days per year available for field toork. 
Farm No.... 
By record.. 
By estimate 
1 
2 
3 
4 
5 
6 
7 
8 
9 
225 
221 
208 
203 
220 
216 
215 
221 
203 
212 
207 
182 
205 
203 
202 
212 
212 
216 
10 
218 
206 
The average of the 10 estimates is 209 days and of the 10 records 
212 days, a difference of only 1J per cent of the total. Considering 
the fact that the quantity here under consideration actually varies 
considerably from year to year and that the records are for a single 
year, the agreement between the estimates and the records must be 
regarded as very satisfactory. 
INVESTIGATIONS BY C. M. HENNIS. 
In cooperation with the North Dakota Experiment Station the Of- 
fice of Farm Management secured the data given in Table VII. 
Table VII. — Acres ploived per day. 
Number 
Records. 
Estimates. 
of horses. 
Number \ 
Number 
of Average. 
of esti- 
Average. 
records. 
mates. 
Acres. 
Acres. 
3 
15 
2.81 
1 
2.73 
4 
32 
3.83 
16 
4.26 
5 
60 
5.02 
37 
5.17 
6 
15 
5.55 
10 
5.61 
When it is remembered that the numbers averaged are in most 
cases very small and that the farmers making the records were not 
the same as those giving the estimates, but were located in the same 
general region, it must be admitted that it is possible to get just about 
as reliable results from farmers' estimates as it is from the most 
careful records provided the questions asked the farmer are within 
the range of his experience and thinking and provided the number 
of estimates is large enough to permit the proper working of the 
law of averages. % 
CASE OF A GEORGIA FARM. 
In a farm management survey it happened that one enumerator 
obtained the record of a certain farm from the overseer at the farm, 
while another enumerator obtained the record of the same farm from 
the manager at his office in town. In both cases the record was given 
