When evaluating an interview's results, a key principle to keep in mind is that it's Highly recommended to start your evaluation of the interview right away after the candidate leaves while everything is still fresh in your mind.


Step 1:  Start from the beginning of your notes and note down each piece of evidence either outlined by the candidate or if it was observed by you.


Step 2: Relate each piece of evidence to each competency or skill from the job analysis performed and remember that each evidence can relate to more than one competency.


Step 3: Contrary evidence: Ensure each piece of negative evidence is balanced by contrary evidence or at least a question seeking contrary evidence was asked to the candidate to give him/her a fair chance before you rule a piece of evidence as negative.


Seeking contrary evidence: Throughout the interview, if you start to get a negative impression or sense that the potential candidate may have weakness in some specific competency or skill, do not take that forgranted before trying to seek contrary evidence for the sake of being fair to the candidate. Frame a question or two to focus on that suspected weakness to confirm or seek contrary evidence.


Step 4: Watch out for any of your personal biases or subjective opinions


Step 5: Weigh both positive and negative evidence you have, it is also recommended to use some sort of a rating system like the example shown below:

5 Excellent Meets competency
4 Good Meets most of the competency description
3 Fair Meets more than half of the competency description
2 Weak Meets less than half the competency description 
1 Poor Meets almost none of the competency description 
0 No evidence  No evidence shown of the competency