The assessment center is a method whereby potential candidates for a job are exposed to a series of tests. These tests are conducted by different people who are known as assessors and last for many hours or even a day. These tests are used when the job requires a person with strong interpersonal skills such as in management positions and when the skills required cannot be assessed with conventional methods. The testing process involves exercises in which the response of the candidate is observed. It also involves behavioral tests where the reaction of the candidates to a particular situation is observed.

The method was originally for selection in the armed forces. Gradually, the techniques were adopted by companies.

The exercises used in assessment centers can be broadly classified into three types :

- Individual exercises 
- One-to-one exercises and 
- Group Exercises

In individual exercises, the assessors observe how the individual works. The tests are concerned with analyzing the cognitive ability of the candidate. Planning exercises are also used where the individual has to respond to a particular situation. Case analysis involves a situation where the individual is presented with a scenario and asked to identify the problem and recommend a solution.

One to one exercises deal with identifying the individual’s interaction with another person in a given context. This involves exercises such as role playing usually involving one of the assessors. The scenario may be a situation such as handling an angry customer or talking to an unhappy employee.

Group exercises involve interaction at a group level. The candidates are asked to participate in a group discussion. The discussion can be on a topic chosen by the interviewers. In some cases, the candidates are asked to make decision and then evaluate them. The ability to work as a team and the ability to effectively articulate the one’s point of view is measured here.

In some cases, a self assessment test is conducted where the candidate is asked to assess themselves on selected attributes. The ratings made by the candidates are compared against those made by the team of assessors. In most cases, the two sets of rating should match.

The quality of the selection process depends on the integrity of the assessment center. Hence, it is important that the assessment center is developed carefully with organizational concerns in mind.

The different steps in the development of the assessment center are 

- Selection of criteria: The criteria should be attributes that are related to the job functioning. The number of criteria should not be more than six. This enables the assessors to focus on the criteria 

- Development of the exercises: The exercises should be developed to reveal the criteria which are required for the job. The rules of the exercise should be clear and unambiguous.

- Selection of assessors: The assessors should be experienced in the field. It is important to look into their credentials and experience 

- Developing checklists for assessors: Developing a checklist for measuring the performance of the candidate prevents personal bias and subjectivity. 

- Ensure that the assessment center is properly functioning: It is important that all the tools required for the assessment center are functioning before the arrival of the candidates.