Please help me correct this IELTS task 2 essay (topic: inside promotion)

Topic: In companies, promotions to high positions should be given to employees inside the company and not to somebody outside the company or new hiring. What is your opinion on this?

(267 words)

Whether higher positions should be given to insiders or new employees is a debatable issue in business management. The given statement proposes the choice of in-house hiring. It is still necessary to consider the advantages and drawbacks of this choice.

There are many benefits in recruiting insiders. Firstly, no prior training is necessarily delivered due to a familiarity of these employees to their companies. Secondly, they understand deeper than outsiders about the visions, and general working of the companies. Therefore, they tend to accomplish tasks and fulfill the company's goals better compared to new candidates. Last but not least, this is a choice called "killing two birds with one stone". In-house hiring also provide benefits to existing employees. They get chances to be promoted, which make them feel rewarding after years of dedication to their companies. The more pleasure promoted employees express, the more productivity the companies may achieve.

However, there are some disadvantages of inside promotion that need to be carefully considered. On the one hand, regular inside promotions make current employees take promotion for granted as they have worked for a long time. Therefore, this create their illusions and latter disappointment for not being promoted. On the other hand, if promotion is rare occasion and sole candidate is chosen, the others will definitely feel unfair.

In my opinion, a hiring decision need to be made for the best interest of the companies. This means that either inside hiring or new recruitment for higher positions is a case-to-case decision and need to be considered as option, not custom and compulsion.