Corporate directors may be favorably biased in assessing their own CEO and set their CEO pay at the end of the peer group. This drives other companies to pay their CEOs because peer group norms go up. This is one explanation for the sharp in CEO pay over time. low, less, "ratchet effect", decrease low, more, "peer group effect", increase high, less, "peer group effect", decrease high, more, "ratchet effect", increase