Short Answer No more than 150- 200 words

I/O psychologists are often used to recruit employees, select employees, and retain employees.  In order to hire good people, organizations must have a large number of possible employees from which to choose. The recruiting source must also be effective. Common sources of applicants include;

1) Advertising

2) Employee Referral

3) Employment agencies

4) School Recruiters

5) Walk-ins

6) Internet

Which recruitment source do you consider most effective and why?  As an I/O psychologist, what measures could you take to ensure a large pool of candidates?