A behaviorally anchored rating scales, or BARs, are questionnaires used to assess job-related behaviors. The key feature of a BARs  in human resource management is that each item refers to some specific observable behaviors. A BARs has three columns: one for the person doing the rating, one for a second person involved in evaluating the performance of the person being rated (usually someone who works with that person), and one for an overall evaluation by both raters combined.

A behaviorally anchored rating system is a tool used by employers to measure employee performance. The scale uses descriptive phrases such as «excellent», «good», and «needs improvement» to describe the quality of an employee's work. BARS are also used by managers when evaluating their employees' performance, as well as by employees themselves when assessing their own work performance.

The following are some examples of how BARs have been used:

• To identify the best employees for a particular position from among several candidates (for example, the best salesperson for a particular territory) by comparing their scores on each item of a rating scale that measures certain aspects of performance in that position;
• To evaluate the effectiveness of training programs in improving performance;
• To determine which factors contribute most strongly toward successful performance in different types of jobs or situations.

By learning the definition of a behavioral-based rating scale, you can determine how you can measure it in your own company. The BABS process requires you to:

1. Select a set of behaviors that will be measured by the rating scale and anchor points for each item on the scale. The anchor points should be selected so that they represent clearly distinguishable levels of performance.
2. Develop short questions or statements describing each behavior in clear, simple language that can be easily understood by those being surveyed.
3. Have employees complete anonymous surveys regarding their perceptions of how frequently they perform each behavior at work over time (or across different jobs).

There are a lot of advantages of the rating scales in HR, but also — some disadvantages. 

Pros:

• Easy to use. The BARS system is easy to understand and implement, making it a good option for organizations that are new to performance management.
• Universal. This rating model can be used in any industry or sector, no matter what type of work your employees are doing or where they're located around the world.
• Cost-effective. Because BARS requires less time than other methods of performance management (such as goal setting), it doesn't require an investment in expensive software or training programs — just some simple tools like sticky notes or pens.

Cons:

• BARS in performance appraisal is not a perfect system. It can be difficult to determine the anchors and endpoints, which are necessary for creating a scale. 
• It may also take time to train people in your organization on how to use BARS effectively so that they know what questions they should be asking customers or clients when they're conducting customer surveys.