A large applicant pool can have a diverse candidate population with different backgrounds and experiences. Education, for example, is one of the main areas of experience organizations consider. Candidates have various levels of education experience — whether it's a high school diploma, associate's degree, or bachelor's degree. When the goal is to recruit top talent, you may think that the higher the level of education the applicant has achieved, the better he or she will perform. This causes you to narrow your applicant pool via a higher threshold, only to later realize you're struggling to keep your candidates around since the smaller applicant pool required you to make sacrifices in other areas to fill vacant positions.
FurstPerson compared level of education to six different performance metrics for one insurance organization and found a candidate's level of education did not make a difference in his or her performance. Focusing too much on education can narrow your applicant pool to the point where you are now opening yourself up to other areas that actually can affect performance — and more importantly, attrition. By keeping your organization away from meaningless thresholds, you can focus on narrowing your applicant pools in places improve retention —without the worry of performance.
("The Best job Candidates Don't Always Have College Degrees," The Atlantic September 2015)