Full context:   The Big Five model originated from the lexical hypothesis, which suggests that the most important personality traits are encoded in language. Raymond Cattell built upon earlier lexical work by reducing thousands of descriptors to 16 personality factors, later clustered into five global traits, which some consider the "original Big Five". Ernest Tupes and Raymond Christal then analyzed peer ratings of U.S. Air Force officers and derived five core dimensions: Surgency, Agreeableness, Dependability, Emotional Stability, and Culture—an approach later popularized by Warren Norman. In the 1980s, John M. Digman and colleagues consolidated evidence from previous studies and reaffirmed five major traits, while Paul Costa Jr and Robert R. McCrae developed the NEO model, starting with three factors and expanding it into the widely accepted Five Factor Model (FFM). These four sets of researchers used somewhat different methods in finding the five traits, making the sets of five factors have varying names and meanings. However, all have been found to be strongly correlated with their corresponding factors.