Employee selection is the process of hiring individuals. It is the part of the overall staffing process of the organization, which also includes HR planning, recruitment, and retention activities. By doing HR planning, the organization projects its likely demand for personnel with particular knowledge, skills, and abilities, comparing that to the anticipated availability of such personnel in the internal or external labor markets. During the recruitment period of staffing, the organization attempts to establish contact with potential job applicants by job postings within the organization, advertising to attract external applicants, employee referrals, and many other methods, depending on the type of organization and the nature of the job in question. Employee selection begins when a pool of applicants is generated by the organization's recruitment efforts. During the employee selection process, an organization decides which of the recruited candidates will best fit for a job. Tests designed to determine an individual's appropriateness for a particular position, company or industry may be referred to as personnel assessment tools. Such tests can assist those charged with hiring personnel in both selecting individuals for hire and in placing new hires in the appropriate positions. They vary in the measurements they use and level of standardization they employ, though all are subject to error. Job applicants differ along educational and work experience, personality characteristics, and innate ability and motivation levels. The logic of employee selection begins with the assumption that at least some of these individual differences are relevant to a person's suitability for a particular job. Therefore in employee selection the organization must determine the relevant individual differences needed to do the job and identify and utilize selection methods that will reliably and validly assess the extent to which job applicants possess the needed knowledge, skills, and abilities. The organization must achieve these tasks in a way that does not illegally discriminate against any job applicants on the basis of race, religion, sex, national origin, or disability. Thus, employee selection is one of the two major ways to make sure that new employees have the abilities required to do their jobs.