RELATION OF LAND INCOME TO LAND VALUE. 
11 
between the census values and these county average sale prices are 
shown in Figure 4. When the census value is higher than the average 
sale price the difference is designated as plus; when it is less than 
the average sales price the difference is designated as minus. 
The average sale price should not be regarded as an absolutelv 
true average price for each countv. In most of the counties the 
average sale price is based upon the transfers of 200 to 300 farms 
only. It may well be that the farms sold may be better or poorer 
farms, on the average, than the average of all the farms in the county. 
Therefore the average sale price would fluctuate above and below 
the true average, depending upon whether farms better or poorer 
than average had been sold. 
However, the Wisconsin Tax Commission and T. A. Polleys, of the 
Chicago & North Western Railway Co., have attempted to get average 
DEVIATION IN DOLLARS OF THE CENSUS LAND VALUES 
FROM ACTUAL SALE PRICES IN 1920 
Fig. 4.— The deviation in dollars of the average census land values from the average actual sale 
price, by counties is shown on this map. When the census value was above the average of the 
sale price, the deviation is designated as plus, when below, as minus. 
sales prices that are representative of the entire county by the assess- 
ment ratio process. This consists in finding the ratio of assessed 
value to sale price on the farms that were sold. It is then assumed that 
this ratio would have obtained for any other group of farms which 
might have been sold. Then the average assessed value for all the 
land in the county is divided by this ratio to get the true value of 
land for the entire county. The average sales prices in Wisconsin. 
Illinois, Iowa, Nebraska, and South Dakota are derived in this way. 
The average sales prices may not be as highly correlated with county 
average productivity as the census values are. They will, however, 
serve as a check on the census values for a general upward or down- 
ward bias. Fluctuations of the census values about average sales 
prices for particular countries can not be considered of any signifi- 
cance. Only a general upward or downward tendency can be re- 
garded as of importance. 
