The main advantages of internal recruiting is that you will have an individual who already knows your corporate culture, and promoting within encourages employees to remain with the company and increase their productivity in hopes of being promoted. The main advantage of hiring outside the company is that you will have someone with new ideas who is not stifled by your current practices.
When you recruit from within, you are sending the message that the company values its employees and wants to invest in them for the long-term. In these days of economic uncertainly, employees will be more productive even if they feel they are underemployed because they see opportunities for advancement. It is very costly to recruit and hire new employees. The cost is greatly diminished when the employee already works for the company and is being promoted. The learning curve to full productivity is also much shorter.
The disadvantages of promoting within a company are the potential corporate snare of valuing only the ideas of your company’s status quo and the resentment that might be felt by those who feel they are passed over. When recruiting within, it will be true that many employees will feel that they can do their supervisor’s job, when in reality they cannot. This can lead to conflict.
When you recruit outside your company, you have the advantage of casting a wide net through the internet and networking. There are currently many individuals who can do the work for less than you would normally offer, whereas an employee within the company would want a raise as well as a promotion. Recruiting from outside also brings in people who have successful ideas from other companies that can be adapted to yours.