A job analysis is the process used to collect information about the duties, responsibilities, necessary skills, outcomes, and work environment of a particular job. You need as much data as possible to put together a job description, which is the frequent outcome of the job analysis.
An interview is a formal meeting between a job seeker and an employer. The employer will ask questions to determine whether the job seeker is an appropriate fit for the job and for the company. The job seeker will ask the employer questions to obtain enough information about the job to decide if the job and the company is the right fit.
The interviewer wants to know, not that you can do something, but that you have done it. He or she, prior to the interview, determines what competencies are required for the position. Then the interviewer develops a series of questions that will allow him or her to find out if you, the job candidate, possess the necessary competencies to perform the job.
These tests aim to provide a potential employer with an insight into how well you work with other people, How well you handle stress, and whether you will be able to cope with the intellectual demands of the job. These tests can be split into personality tests and aptitude/ability tests.
An assessment centre is an event organized by employers as part of their selection process. Usually assessment centers are for candidates who have successfully negotiated the first interview so reaching the assessment centre stage is a great achievement.