Let's face it. Hiring a new sales rep is less than a perfect art or science. And many sales people simply don't work out or perform as expected. This is largely due to the fact that many sales managers make a variety of mistakes when hiring sales reps.

Here are 15 of the most common mistakes sales managers make when hiring new sales reps.

1. They conduct low quality interviews. Most sales managers have never learned how to conduct a high- quality interview. This isn't their fault; it's just that most companies do not teach managers how to conduct great interviews.

2. They fail to ask tough, probing questions. Most hiring managers ask questions about work history, experience, and general performance. However, they neglect to ask questions about gaps in a candidate's resume and they are uncomfortable asking probing questions about previous performance and that challenge a potential candidate.

3. They get mislead by candidates who interview well. Many sales people have a tremendous ability to "schmooze" and make a great first impression. This often leads to the sales manager to feel good about a particular candidate. However, just because you like someone does not mean they will perform well once they are hired.

4. They rely on instinct or gut feel. Many a sales manager has hired a rep that made a great impression (see the previous point). This is often caused because the candidate had a similar personality style to the hiring manager and was able to connect with that individual. However, once hired, the rep does not perform to standard.

5. They do not check references. Checking references is not an enjoyable task especially when you have a multitude of other tasks demanding your attention. Connecting with previous employers is a challenge and many managers don't want to appear skeptical so they neglect this step in the recruiting process. Or, they delegate the reference check to an assistant who is not fully versed in the questions they need to ask to gain a better understanding of the candidate's previous work performance.

6. They do not consider the type of sales person they need for their specific sales environment. Different sales environments require different skills sets. For example, if a business requires a sales rep to make dozens of cold calls but they hire someone who is not proficient at this, that rep's results will be less than satisfactory.

7. They do not make use of hiring tools such as assessments. Assessments can help sales managers identify several things. The first is the type of sales environment the rep will be required to work in. Second, the aptitude the rep has for selling. And third, the potential shortcoming and possible problems a candidate may experience in the particular position.

8. They don't ask candidates exactly how they will achieve results. Once again, this requires that you ask probing questions to determine exactly how the potential employee will generate the sales that you require.

9. They talk too much during the interview. Conducting an interview means giving the applicant sufficient air time. Too many managers talk about the company and their goals instead of asking questions and allowing the rep to talk. The general rule of thumb is to make sure that the candidate talks at least 70 percent of the time.

10. They don't properly prepare for the interview. Because sales managers are extremely busy they often ask their assistant to schedule interviews and only look at the resume once the candidate is in their office. Proper preparation means reviewing the candidate's resume beforehand, identifying possible gaps and determining key questions that must be asked.

11. They hire to "fill a gap." It is not uncommon for sales managers to race through the recruiting process in an effort to quickly hire someone because they need a rep in place. After all, hiring reps is seldom a task that managers enjoy. In these situations, managers focus on the positive aspects of the applicant and neglect to see their possible shortcomings. This often leads to "hiring remorse" once they discover that the rep is not entirely suitable.

12. They allow interruptions during the interview. Sales managers have dozens of tasks and projects on their plate at any given time and often allow other staff including their assistant to interrupt them during an interview. Effective interviews must be conducted without distractions and interruptions.

13. They only interview people who have industry experience. Unless your industry is highly technical, you should consider people who do not have experience in your industry. Many people are fully capable of performing well in a new industry providing they are suitable fit to your particular sales environment. Industry experience brings baggage and preconceived idea. Candidates who do not have industry experience often bring a new perspective to the sales role.

14. They do not get second opinions. Interviewing a sales rep requires more than one perspective. Effective sales managers get other people in the company involved in the interviewing process and they compile all of the feedback before making a hiring decision.

15. They fail to seek clarification. I have witnessed dozens of interviews and noticed that many sales managers take a candidate's comments at face value instead of clarifying vague comments. If in doubt, check it out.

Avoid these mistakes and improve your chances of hiring a top performing sales rep instead of someone who fails to reach their targets.