Selection instrument refers to the method used for selecting a person for recruitment. A company uses several different selection instruments such as written tests, group discussions, and interviews. A company may use more than one instrument for selecting candidates for employment. Interview is the most commonly used selection instrument, and is generally used in combination with other instruments.
Interview involves one or more interviewers talking to the candidate to ascertain his or her knowledge and personality traits. The interviews are generally conducted face to face, bur may also be conducted over telephone or through other options such as video conferencing.
Interview is a highly subjective instrument of selection therefore it has the lowest reliability and validity as compared to other selection instruments. Further the reliability and validity of selection by instrument depends very much on skill of the interviewers.Also the validity of interviewing drops sharply when different persons interview different candidates.
To some extent the reliability of selection by interviewing can be improved by providing guidelines to the interviewers on ways of conducting the interviews and providing a scheme of factors to be considered for evaluation of the candidates.