You teach that is a bad idea to buy an individual stock when the markets are going down. I believe this is a good idea, but I do not see how to do this in any of the many available Unisearch searches. This lacking criteria will now allow a sold stock (due to sell criteria settings) to be replaced on a down market day. This can hurt total results if it followed by more down market days. This can be implemented if a VVC choice were settable in the Parameter field box. One could then set the price change as the Operator and percent change greater than zero as the Value. In fact if they were available one could match their up day requirement to the watch list limits-such as S&P 500, DOW 30, or Russell 2000.
One could also use the concept to prohibit short searches from selling on up days.
If you include this line into the chosen search, the back tester would pick replacements stocks. However, no matter how many candidates were otherwise found they would be eliminated for that day and for as many days as the selected market average was going down (or up for short searches).