      When deciding what type of order to enter, the trader must also takeinto consideration the prevailing spread in the stock he plans to buy orsell, and how many shares his order is going to be. In a study done byLawrence Harris and Joel Hasbrouck17, they found that for orders under 200shares, market orders tend to do better than the prevailing quote (theoffer for a buy order and the bid for a sell order) that exists at the timethe order is entered by 1.73 cents/share in 1/8 point spread markets, by8.24 cents/ share in 1/4 markets, and 11.14 cents/share in 3/8 markets.Clearly, the price improvement received increases as the prevailing spreadwidens. When market orders are of larger size, however, the overall priceimprovements decrease dramatically. For 1,000 share market orders in1/8,1/4, and 3/8 markets, the price improvements are -.09 cents/share, 3.84cents/share, and 2.51 cents/share, respectively.