QUESTIONNAIRES , 
vestigators who go to the sources for their facts. Such in- 
formation is apt to be reliable but expensive. It is indis- 
pensible, however, in hiring some types of employees, such 
as Pullman porters, where integrity and dependability are 
most essential. 
If the subjects of the investigation are employees, these 
same sources of information may be used. 
When the questionnaire is distributed to subordinates by 
an executive who requires it to be filled out, he must explain 
its purpose in a way which will insure a willingness to co- 
operate helpfully. The best way is for the investigator 
himself, wherever possible, to present the questionnaire in 
person, insuring an understanding of the instructions and a 
willingness to give with the utmost frankness the informa- 
tion desired. 
Questionnaires regarding employees may be devised for 
completion by supervisors or fellow-workmen. 
Information about employees may also be obtained from 
company records and tabulated on specially constructed 
questionnaires. 
Much questionnaire information is best secured, not 
through asking the worker or supervisor to fill out a blank, 
but through the expensive but more reliable method of the 
personal interview. People who neglect or refuse to fill in a 
printed form or answer a letter are often glad to give the 
desired facts to some one who comes to them in person. 
Charters (30) has developed the techniques involved in this 
procedure. They include a careful preliminary training of 
the interviewers, as well as a standardization of the ques- 
tions to be asked. 
It must not be forgotten that a scientific method of selec- 
tion bases itself on information whose predictive value has 
been statistically determined. This information about the 
applicant is obtained by tests, rating scales, and question- 
naires at the time of employment. 
The personal interview also has as its main purpose to 
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