Human resources is a term with which many organizations describe the combination of traditionally administrative personnel functions with performance management, Employee Relations and resource planning. The field draws upon concepts developed in Industrial/Organizational Psychology. Human resources has at least two related interpretations depending on context. The original usage derives from political economy and economics, where it was traditionally called labor, one of four factors of production. The more common usage within corporations and businesses refers to the individuals within the firm, and to the portion of the firm's organization that deals with hiring, firing, training, and other personnel issues. This article addresses both definitions.