A selection interview is almost always a live interview during which you meet an executive, a department head or another person with a lot of authority within the company. This is what makes the selection interview different from a screening interview, which often happens on the phone or through video conference and during which you talk to a person from the human resources department.
Often, the interviewer that you will be talking to during the selection interview will be your boss. Selection interviewers sometimes do not have a lot of interviewing skills. Interviewing is not what they do for a living, so they often rely on their intuition in their hiring decisions and want the process to be over as quickly as possible, so that they can go back to their jobs.
If the person conducting the selection interview is indeed going to be your supervisor or a co-worker, you want to reveal your best accomplishments and personality traits and see if you and your potential boss are a good fit for each other. If your intuition is telling you that you are not going to be able to work together with this person productively, think twice about accepting a job offer, even if the salary and benefits look very attractive. While the position may look tempting, in the long run, you will be better off working at an organization where you and your boss are on the same page.
If you are interviewing at a small company, you will often have a combined screening and selection interview. Because the interview is combined, it tends to be long and grueling. This would test not only your job-related skills but also your stamina and motivation as well as how you fit with the organizational culture.
During such interviews, interviewers are looking for strong presentation, specific details about your skills, job experience, education and handling of different job-related scenarios.