The interview assessment can make the decision easier or more difficult. When done correctly, it simplifies the process. So how do you simplify?
There are two strategies that are used to simplify the process of eliminating candidates, grading and ranking. My preference is ranking but more on that in a minute.
In the grading system, each candidate is graded on the key criteria such as skills, personality fit, management style, etc. It is important to grade each candidate immediately after the interview. If there are multiple interviews, the freshest impression will always be the last.
After each candidate is graded, by each member of the interview panel, a gross score can be created. Sometimes the criteria are weighted consistent with the require skills for the position. The benefit of the grading system process is that each candidate gets a fresh assessment based on their interview and not in comparison to other candidates. The down side is that the scoring, the criteria and weighting (if required) must be decided up front.
The ranking system is quite different than the grading system in that each candidate is interviewed before any assessment is made. Each candidate is compared against one another.
At the conclusion of the interviews, each candidate is ranked for each criteria. Again, some criteria may be weighted more heavily than others but the conclusion is a set of candidate rankings.
The benefit of this approach is that the candidates are directly compared and if weighting is used, the best candidate will float to the top. Often with scoring systems there can be equal scores given to a candidate. In the ranking system one candidate must be ranked higher than another, even if the differences are subtle. The biggest downside is that sometimes the last candidate interviewed receives a slight benefit because the information is freshest. This can be overcome with good notes.
Finally my preference for the ranking system is that it forces a decision between candidates. The act of ranking is in itself a decision maker and forces choices to be made. The end result is a clear cut favorite for the