The contribution of Transactional Analysis is not credited to Kurt Lewin. Lewin (1890-1947) was a professor and taught at schools such as the Massachusetts Institute of Technology (MIT), Cornell University, and Duke University. Action research refers to either research that is attempting to solve a particular immediate problem, or a long-term problem-solving approach by teams.
The Unfreeze-Move-Freeze Model refers to the three stages of change, for example an ice block needs to be melted, poured into a mold, and refrozen into the new shape. Force Field Analysis is a way to look at whether to make a change, and a T-Group is a type of group training where individuals learn about themselves.