FOREST TAXATION IN THE UNITED STATES 105 
Studies of assessment ratios have frequently been made by econo- 
mists for the purpose of obtaining information as to various aspects 
of assessment practice. The purposes indicated in these studies have 
been to measure inequalities in assessment among individual owner- 
ships, among different political divisions, between country and city 
real estate, between large and small properties, and among various 
classes of owners. The results have been used to throw light on the 
causes of inequalities and on methods of improving assessment prac- 
tice. Much of the technic which has been developed in these studies 
was used in the additional investigations which seemed desirable from 
the standpoint of the forest-tax investigation. The results of these 
studies will be drawn upon later in connection with the results of the 
original investigations. 
Since studies of assessment ratios made by other investigators have 
not been especially concerned with conditions in forest regions or with 
the inequality that may exist among different kinds of forest property 
and other property, additional studies of these subjects seemed neces- 
sary. In order that the results of these studies may be properly 
understood, it 1s necessary to indicate more specifically the kind of 
data that were used. 
METHODS OF ESTIMATING TRUE VALUE 
GENERAL 
The numerator of the assessment ratio is the assessed value of the 
property or group of properties, which is a matter of public record. 
The denominator of the assessment ratio is the true value of the prop- 
erty or group of properties at the assessment date and is therefore of 
necessity an approximation. As explained in a preceding section of 
this part, true value may be estimated by appraisals or approximated 
by considerations realized in sales. 
Appraisals may be made intensively; that is, through a detailed 
study of each property. In arriving at an opinion of value, the 
appraiser is Buide d by knowledge of transactions in comparable prop- 
erties and of the values realized in those transactions. His experience 
enables him to give due weight to the different factors affecting value 
in making comparisons between each property sold and the property 
being appraised. If appraising on a large scale, he will require maps, 
tabulations, and other statistical aids. “Such intensive appraisals by 
experts afford the best estimates of value, but even they are of course 
not infallible. 
Appraisals may also be made i in a more extensive fashion, involving 
a rapid examination and giving consideration only to the more impor- 
tant factors affecting value. Such appraisals are reliable only when 
they have no persistent bias and when they are aggregated in large 
enough groups so that errors may be presumed to offset each other. 
Owing to the difficulty of obtaining reliable expert appraisals in 
sufficient number to test assessment, it has been the usual practice to 
use considerations realized in sales as if they were true values. Since 
each sale represents an actual agreement as to value between buyer 
and seller confirmed by a transaction, it is prima facie evidence of 
the value of the property at the time and under the conditions of the 
sale and is not subject to the suspicion of bias or fallible judgment 
that necessarily attaches to the finding of an appraiser. However, 
