 While there are many personality questionnaire used in Big Five research (such as the NEO-FFI, HEXACO, TDA, BFAS, and BFI), it appears that the NEO-PI-R, developed by the prominent personality psychologists Robert McCrae and Paul Costa, continues to be the most popular choice. Here are three examples of items participants might have to respond to in taking it (NEO-PI-R Item Booklet-Form S: 3):