What is effectiveness of position? How is it defined? What graph? If you provide some more information, or links to where the information can be found we might be able to provide some more assistance. wabbit :D

A quick scan of the users manual will give you the answer! Page 337 in my version 9. wabbit :D

MS has quite a reasonable help function installed with it. There isnt much in the manual that isnt in the help, and not much in the help that isnt in the manual. Open the system tester and select the help button. Look in the Positions Report section for this: Positions Report This report summarizes details about each position that occurred during the test, starting with whether the position was long or short and how many units it traded. The graph at the top of this report represents the distribution of trade efficiency over all of the profitable trades that occurred in this simulation. Basically, if all the peaks appear to the right of zero, the system is well tuned. If all the peaks appear to the left of zero, the system is poorly tuned. The rest of the information is organized in categories, described below. Opening Price - The security's price when the position was opened. Bar - The position opened on this bar. Date - The position opened on this date. Efficiency - This is the percentage of possible profit this position made. For example, say you bought a stock for $10. If the stock fluctuates between $20 and $10 while the position is open, and you sell at $15, your efficiency is 50%. If you sell at $20, your efficiency is 100%. Commission - How much your broker charged to place the order. Value - What the securities in the position were worth when they were bought, plus commission. Closing Price - The security's price when the position was closed. Bar - The position closed on this bar. Date - The position closed on this date. Efficiency - This is the percentage of possible profit this position made. For example, say you bought a stock for $10. If the stock fluctuates between $20 and $10 while the position is open, and you sell at $15, your efficiency is 50%. If you sell at $20, your efficiency is 100%. Commission - How much your broker charged to place the order. Value - What the securities in the position were worth when they were sold, plus commission. Most Favorable Price - The best price the security reached during the test (highest for long positions, lowest for short positions). Bar - The bar in which the most favorable price occurred. Profit - How much money the position would have earned if it had closed with the most favorable price. Most Adverse Price - The worst price the security reached during the test (lowest for long positions, highest for short positions). Bar - The bar in which the most adverse price occurred. Profit - How much money the position would have lost if it had closed with the most adverse price. Hope this helps. wabbit :D P.S. All legal copies of MS come with a manual.

Are the results dramatically different? Are you using realistic market prices? Do the calculations take brokerage into account? Have you included any delays, in the entry/exit signals and/or the exits themselves? I don't use mechanical trading systems so I dont use the tester that much, but I suggest you have a look through the help sections, do some experimentation, see if you can figure out why you calculations differ from the packaged calculations. Patrick might even be so good as to ask the code-cutters for the complete algorithm? and post it for you to peruse? There are a lot of unknown factors to be considered. Known unknows can be dealt with, its the unknown unknowns that cause trouble. wabbit :D P.S. Now its time for bed - more tomorrow!?!?!? oz_pdt_01q