Conducting a job interview looks a lot easier than it is. Many hiring managers take this step in the hiring process for granted  and don't invest the time, work and concentration that effective job interviews require. Above all, they don't prepare enough and end up winging it.  

Even if you feel you know how to conduct a job interview, this stage of the hiring process is where you are most likely to falter. Interviewing mistakes — such as succumbing to interviewer bias or failing to follow a standardized list of questions  — can lead to bad hiring decisions, which can be  costly  for your company.

Here are seven  of the all-too-common job interview mistakes hiring managers make, with tips  on how to avoid them:

1. Bringing interviewer bias

In the world of scientific research, a scientist’s expectations can influence the outcome of an experiment. Similarly, a hiring manager may develop a bias based on expectations about an applicant in the context of an interview. For example, a manager might believe that a prospective employee  who comes highly recommended by a colleague is prequalified and better suited to the position than an unknown. Interviewer bias can also be more subtle — for example, when an employer unconsciously favors an applicant whose first name is the same as her generous, hard-working uncle.

The solution: Hold multiple interviews.

The best way to overcome interviewer bias is to have several qualified individuals meet and question each candidate for a position. The first interviewer, for example, might be a human resources manager, while the second might be the supervisor the applicant would report to. The company  owner or division head might conduct a third. Alternatively, a committee composed of a senior executive, a manager and team members could chat with  each potential employee and compare answers.

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2. Apples vs. oranges

Interviewers often believe they are fairly consistent in the  evaluation process, when in reality the interviewers are assessing variable criteria.  One major difference between interviewers who have a knack for hiring  winners and those who don't is nothing more than simple discipline. Skillful interviewers think through the process and tend to follow the same method every time, with variations that they tailor to individual situations. Unsuccessful interviewers tend to wing it, creating a different routine for each interview and entering unprepared. The hidden danger of a lack of planning: You deprive yourself of the one thing you need the most as you're comparing candidates — an objective standard for evaluating potential employees.

The solution: Ask the same questions every time.

Before scheduling the first round of in-person interviews with candidates who passed the phone screening for the position, create and prioritize a standard list of appropriate interview  questions. These should be based on the key skills and aptitudes required for the job. Generally, a standardized interview question list can be grouped into three broad categories: experience (to review education, job skills and work history), aptitude (to explore special abilities and willingness to learn) and interpersonal skills (to assess their ability to work independently, as part of a team or in a leadership capacity). Interview questions touching on professionalism, judgment and career aspirations can also be useful.

3. Being dazzled by a halo

The  halo effect  is a term managers often use to describe a situation in which the interviewer becomes so enraptured by one particular aspect of the job candidate —  appearance, credentials  or interests —  that it colors all their other judgments. This might cause an interviewer to overestimate the qualifications of a potential employee  who went to their own alma mater. A negative detail can have the opposite effect and cause a candidate’s qualifications to be underestimated. Interviewers are only human. You can't always help yourself from placing too much significance on one part of their  overall presentation. At the very least, however, be aware of your halo-effect tendencies and do your best to keep them in check.

The solution: Be analytical.

One way to overcome the halo effect and  improve your selection process for hiring  is to be sure that you evaluate the prospective employee  on each key skill and aptitude needed for the job. Appraise each aspect analytically — you could even assign a score from 1 to 5. This allows you to make sure there’s evidence for your positive (or negative) impression and give you a more realistic basis for comparison.

4. Contrasting the candidates

When interviews are scheduled close together on a single day, a contrast effect may come into play and distort how potential employees  are evaluated. For example, stronger job candidates interviewed right after weaker ones may appear to be stronger than they really are. 

The solution: Space interviews out — and take good notes.

It’s worth considering the contrast effect when scheduling interviews. If possible, leave a little time between conversations with prospective hires to review interview questions and answers objectively and cleanse your palate. Just being aware that contrasts between potential employees  could be coloring your judgment can improve your objectivity. Taking good notes and reviewing them later also helps give a better sense for how the people in the running for the job  really stack up.

5. Neglecting interview prep time

Failing to give the interview process the time and effort it deserves is, by far, the main reason hiring managers  fail to reveal useful information about a person. You can probably understand why they frequently neglect to take the necessary steps to prepare for interviews, conduct them diligently and evaluate the results in a thoughtful manner: They're busy. Everybody's busy. Time is at a premium. But your job is to make every interview you conduct count. 

The solution: Stick to a schedule.

If you want to objectively compare each potential hire's answers, give them the same amount of time, whether it's 15 minutes or a full hour. Encourage all managers involved in the hiring process  to  have the same goal.

6. Forgetting the details

No one's memory is perfect, and that can lead to interviewing mistakes. After interviewing dozens of prospective hires, it's inevitable that an employer might have trouble remembering details or may confuse one applicant's qualifications or answers with another.

The solution: Keep meticulous records.

Take careful notes during each conversation  to make it easier to compare potential hires  and reveal gaps in information. Note taking also helps offset a natural tendency to place too much importance on an individual's performance. A person who interviews well isn't necessarily always going  to be a  good hire — a reserved, unassuming candidate  may end up working out as  a better match for your  workplace. 

7. Talking too much

A good interview really boils down to pace, perception and patience. If you're talking more than 20 percent of the time during a job interview, you're talking too much. You can —  and should —  react, comment on and build on the answers that candidates give in job interviews. And you should certainly respond to  their questions about your office, work-life balance and your typical day. But  bear in mind: The only thing you discover about potential hires  during any session where you're doing most of the talking is how they listen.

The solution:  Let them drive.

The interviewee should carry most of the conversation. Plus, probing through active listening — for example, letting the job candidate's comments spark related questions — is a critical interviewing skill because it allows you to gain valuable information you'd miss if you did most of the talking. 

Identifying and screening job candidates can take a lot of time and energy. If you need some help evaluating new hires for your company, contact Robert Half. We are experts at finding highly skilled professionals  who meet your job requirements in your industry and location.

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