imbalances exist in the DOM for like 1 second and the they move or switch to the other side. How do you do it?
When you see changes to orderbook volumes and orders, it can be anyone and anything as long as you have no identification information on the orders in the book. Scalpers normally trade on instruments where they can take any of the sides - e.g futures or forex - which are zero-sum games, and you can go short just as easy as you can go long. Some trading applications have the possibility to switch your position, and this can also be set by programmable click-buttons or hotkeys for a program. That way you could switch in the orderbook really quick, but with the DOM - or the ladder - you can also have 1-click trading or use hotkeys... So those are some methods to quickly set sides on how you trade. Scalping is nice in volatile markets - because you reduce risk by limiting the time you are exposed to an investment. Mastering several types of strategies is helpful for the varying conditions of the markets in my opinion. It takes some time to master several different types of instruments - but whatever works, it's all good.
The DOM is just one part of the scalpers tool for success. Time and Sales helps sift through the false information that is sometimes presented on the DOM.
Only one second? The Globex can execute a trade every 13.7 milliseconds (as of May 2008 see news release at http://www.reuters.com/article/pres...008+PRN20080513 ) and can update the DOM even faster (since no price matching logic is involved). Can you process up to 100 DOM updates a second? No, you can't. So you better colocate a bot if you want to compete.
I was under the impression that scalpers didn't really look at price action per se as much as looking at imbalances in the DOM and they just rode the imbalance until it was balanced or reversed. I don't see how this is possible for a human. Imbalances stay imbalanced for less than 1 second.
You are attempting to beat the fastest supercomputers wired directly to the floor. Good luck with that; there's no way the average trader may profit from this small imbalances.