“…This particular issue took center stage after the crash of October 1987, when critics claimed that increased activity in 2 See Clark (1973), Epps and Epps (1976), Grammatikos and Saunders (1986), Harris (1987), and Tauchen and Pitts (1983). 3 Models that rely on different types of traders to develop the relation between trading activity and price formation include Admati and Pfleiderer (1988), Brown and Zhang (1997), Easley and O'Hara (1987), Foster and Viswanathan (1990), Glosten and Milgrom (1985), Holden and Subrahmanyam (1992), Kyle (1985), Shalen (1993), Spiegel and Subrahmanyam (1992), and Subrahmanyam (1991). 4 Bessembinder et al (1996) and Harris and Raviv (1993) labeled this phenomenon differences of opinion, whereas Bamber, Barron, and Stober (1999) pointed to differential interpretation of information as a cause of both volume and volatility.…”