How do organization ensure that they are hiring the best people and putting them into the right position?

Generally, for each position:

1. "What does the job entail?"
- Have a comprehensive job description.
2. "What skills and strengths are needed to do this job well?"
- Identify the skills and strengths needed.
3. "How do I know IF this person can do the job and/or how well can he do it?"
- Have an interview "script" - and a "grading system" of sorts... as in a "score" for each answer.

Does this give you the basic gist?