As per SHRM, 63% of hiring decisions are made within the first 4.3 minutes of an interview. So basically you spend next 30 minutes or so in rationalising your decision. Reason - interviewers are biased. This article charts out ways to remove bias while conducting interviews.
1: Remove self bias
Yes, everyone has his / her own bias. It's in human nature. We cannot remove biases but by identifying our biases we can ensure that our decisions are not affected. It is a general tendency to give positive feedback to candidates who are similar to oneself. Similarly, if we hate or dislike something, we intend to associate with negative feedback.
Awareness of self bias is the key here.
One should be aware of his/her own biases and ensure that during the interview these should not cloud interview observations. Identify themes wherein you get elated if the same theme is present or demonstrated by the candidate. Note it down, that is your bias. Be conscious of similarities between yourself and the candidate. If you had any negative experiences associated with anything which is demonstrated or associated by the candidate, take a break. You might have already formed negativity bias.
2: Control the interview
These days candidates are smart enough to search interviewer's background to play to their advantage. Haven't you noticed that the candidate has already visited your linkedin profile the previous day? Candidates play the game of tweaking the resume & interview to your bias. Don’t go on asking questions one by one as mentioned in the resume. That way you are allowing candidate to control the interview. Don’t ask questions on competencies mentioned in the resume. The best way is to start with JD itself. By covering a variety of topics as per job requirements, you focus on compatibility with the job.
When YOU select the topics, YOU are in control of the interview
3: Conduct interview in scientific way
Interview if conducted in a structured process which relies more on scientific method removes possibility of bias creeping in. Leverage competency based interviewing technique. Look for behavior / traits within candidates responses. Try to look for:
Past Performance as a Predictor.
Projective Behavior - how they will perform in future scenarios.
Conceptual Knowledge of the required skills (theoretical or practical).
4: Probe, Probe & Probe
Remember Toyata's 5 whys or fish bone diagram. In similar fashion try to go deep into the scenario. That way you will get to know the conceptual understanding of the candidate, experiential learning and ability to respond in future.
What / How / Why / When / Where?
What have they done? Ask about a Specific Situation or Problem? How have they done it? What was their Approach / Action? Why did they do it? What was the result? Will they do it differently? When? Why? What have they learned? Where else have they applied this learning?
Look for Repeated evidence to competency and future repeatability. Try to link Reasoning / Result / Learning / Application in other questions.
A good practice is to have Follow Up & Substantiate questions
Self Appraisal Questions like What is it about you that enabled you to develop that solution? or Why did you get promoted to lead the Sales organization? or How did you manage to get such a high GPA in college? will show you the thought process of the candidate.
Third Party Self Appraisal Questions like If I contacted your Manager (Direct Reports / Co-workers), what would they say why you were promoted so quickly to lead the Sales organization? will again reinforce their behavior.
5: Cross verify
Once the interview is over, take some time to verify your observations with the responses by the candidate. Go through entire interview process in your mind and try to link candidates' responses and behavior. Check for consistency throughout the interview process. If the candidate is showing attribute of team management in question 1 but is lacking in question 5, then you need to be careful. Many interviewers even go to the extent of calling candidate's references to verify their observations.