List three types of needs according to David McClelland.

David McClelland, an American psychologist, proposed a theory of motivation that is often referred to as the Three Needs Theory, or the McClelland's Theory of Needs. According to McClelland, there are three types of needs that are key drivers of human behavior in the workplace and in other contexts. These needs are:

1. Need for Achievement (nAch): This is the drive to excel, to achieve in relation to a set of standards, and to strive to succeed. Individuals with a high need for achievement seek to accomplish challenging goals, take calculated risks, and prefer to receive feedback on their performance. They are often driven by a personal standard of excellence rather than by the desire for external rewards or recognition.

2. Need for Affiliation (nAff): This need pertains to the desire for friendly and close interpersonal relationships. People with a high need for affiliation value being liked and accepted by others. They prefer cooperation over competition and seek to avoid conflict. In a work setting, they might prioritize team work and a harmonious work environment.

3. Need for Power (nPow): This need is the desire to have control or influence over others. Individuals with a high need for power want to make an impact, have authority, and be influential. McClelland distinguished between two types of power: personal power (the desire to control others) and institutional power (the desire to organize the efforts of others to further the goals of the organization). Those with a high need for institutional power are often interested in leading and facilitating the success of a group or organization.

McClelland's theory suggests that these needs are learned and socially developed, and that the dominant need in an individual is a predictor of their behavior and actions in various situations. Understanding these needs can be useful for managers and organizations in designing work environments, motivating employees, and leading teams effectively.