A major function of I–O psychologists is to design recruitment processes and personnel-selection systems. Personnel recruitment is the systematic process of hiring and promoting personnel. It includes developing job announcements, placing ads, defining key qualifications for applicants, and screening out unqualified applicants. Personnel-selection systems employ evidence-based practices to determine the most qualified candidates for a job. Common selection tools include ability tests, knowledge tests, personality tests, structured interviews, the systematic collection of biographical data, and work samples.

Recruitment

Recruitment is defined as the search for potential applicants for actual or anticipated vacancies. It is the first step in the hiring process. No matter how a company recruits, the goal of a recruitment strategy is to produce viable applicants who fit in with the company's needs and values. Therefore, it is beneficial to attract not just a large quantity of applicants, but a group of individuals with the necessary skills for the position.

Selection

The next step in the hiring process is selecting new employees from the pool of qualified candidates. After obtaining a large, qualified applicant base through recruitment, managers need to identify the applicants with the highest potential for success in the organization. Selective hiring is critical because it reduces future staff turnovers, reduces costs, and increases morale and productivity. To find the best fit, managers create a list of relevant criteria composed of critical skills, behaviors, and attitudes for each position. It is important that managers select candidates based on how they fit with the culture of the organization, as well as their technical skills and competencies.

Types of Selection Measures

Industrial and organizational (I–O) psychologists use a variety of measures to select applicants who are the best fit for a position. The main goal of these tests is to predict job performance, and each test has its own relative strengths and weaknesses in this regard. When making a hiring decision, it is critical to understand the applicant's personality style, values, motivations, and attitudes. Technical competency can be acquired by new employees, but personality is not easy to change.

Interviews

Interviews are one of the most common ways that individuals are selected. The best interviews follow a structured framework in which each applicant is asked the same questions and is scored with a standardized rating scale. In this way, structured interviews provide more reliable results than unstructured interviews.

Job interview

Interviews are one of the most common methods of selection. Structured interviews provide more reliable and consistent scoring results than unstructured interviews.

Personality Testing

Another tool used for selection is personality testing. Personality tests can provide an accurate analysis of an applicant's attitudes and interpersonal skills. These tests can reveal a variety of things about an applicant, such as how well the applicant gets along with others, self-discipline, attention to detail, organization, flexibility, and disposition.

Ability Tests

Psychomotor-ability tests are used to measure fine motor skills and hand-eye coordination. These skills are important in jobs, like carpentry, that require a lot of hand-eye coordination. Unlike psychomotor ability tests, physical ability tests measure gross motor skills, such as lifting and running. These skills are important in jobs such as construction, where strength is needed.

Work Sample

Another selection technique is to have the applicant complete a hiring assignment. The applicant is asked to complete a task that simulates the actual job. The goal is to assess how well the applicant can learn and perform the tasks.

Validity and Reliability

I–O psychologists must evaluate the validity of these measures in order to determine the extent to which selection tools can predict job performance. Measures have different types of validity that capture different qualities. There are three major types of validity: content validity, construct validity, and criterion validity. 

Content Validity

Content validity refers to how comprehensively the measure assesses the underlying construct that it claims to assess. As an example, let's look at a job interview for a position as a banker. This measure would have low content validity if it assessed whether the candidate was comfortable talking to many different people but not whether they were comfortable with math, because the candidate would not have been thoroughly evaluated on every facet of being a banker. The measure didn't cover the full breadth of what the job requires. 

Construct Validity

Construct validity refers to whether the measure accurately assesses the underlying construct that it claims to assess. This can be evaluated by examining correlations with other measures that purport to assess the same construct. When we ask if a measure has good construct validity, we're asking, "does this test the thing we are interested in testing?" An example of a measure with debatable construct validity is IQ testing. It is intended to measure intelligence, but there is disagreement about whether it measures intelligence, as it claims, or merely one type of skill. 

Criterion Validity

Criterion validity examines how well the construct correlates with one's behavior in the real world across multiple situations and manifestations. For instance, does the measure adequately capture the construct (e.g., work ethic) as it presents in real life (e.g., getting assignments done on time, coming in to work on time, not leaving early, etc.)?

Reliability

The reliability of a measure refers to whether the measure gets repeatable results. Will the recruitment and selection processes that a company uses work every time they need to hire someone, or just once? If their processes get good results every time, those measures can be said to be reliable.