He challenges the students by asking whether they want their careers to be as leaders or followers of opinion. David has many ideas for involving students in the classroom, such as a bingo game where small groups of students compete for a little prize. This uses numerical questions and gets collaboration going, bringing out the competitive spirit. Another is a crossword against the clock. He likes to challenge them with questions like "How would the world be worse off without P values?"! Well, how would it?