:- EMPLOYMENT PSYCHOLOGY 
The line should not be much more than five inches in 
length, otherwise it cannot be easily grasped as a whole. 
The favorable extremes of a series of scales should be 
placed alternately to the right and to the left. Or, better 
yet, the scales may be arranged in an apparently haphazard 
way so far as the position of the favorable extreme is con- 
cerned, but in half the instances it should be at the left end 
of the line. This arrangement breaks a motor tendency to 
check at one side of the page. It helps to reduce the halo 
effect, resulting in more discriminating judgments. 
OBTAINING THE RATINGS 
Regardless of the type of rating scale which is used, ex- 
perience dictates certain precautions. 
Ratings on each person should be obtained from at least 
three competent judges who are thoroughly acquainted with 
his abilities. This is not always possible; but the cautious 
investigator will frankly recognize that anything short of 
this minimum gives him a measure with only very meagre 
reliability. 
To get the most representative measure of each ability in 
each person the ratings of the judges should be averaged, or 
if two out of three of them agree, the judgment of the ma- 
jority should be accepted. 
The raters should be carefully trained in the use of the 
scale. The investigator should go over it with them in de- 
tail to make sure that they understand its operation and the 
pitfalls they are to avoid. 
Most raters are at first unaccustomed to think of men 
analytically. They tend to think in terms of general im- 
pressions, prejudices, or indefinite descriptive phrases. 
Some information will have to be given them about the 
statistics of distribution of abilities and the quantitative 
relationship of differences in abilities. 
The raters should be warned to avoid being influenced in 
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