I created a scan for crossing 200DMA.  However if you run it today before the market opens, the stock $VVUS is not included there.

I want a scan of stocks about to cross the 200DMA, but I am not sure how to do it,  Price Below 200DMA will probably return me too many!!

Thanks

There is no way to create a formula for what will happen, only for what has happened.

One possibility would be to calculate what tomorrow's close would need to be for price to and SMA200 to have the same value and then check for the actual price to be crossing up through this value. There are topics on how to do this for two moving averages.

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But when you set the period of one of the moving averages to 1, that term drops out. So the value that price would need to be tomorrow for price to be the same as the 200-period simple moving average would just be:

AVGC199

Making our potential cross formula be very similar to the formula for the cross we are attempting to anticipate:

C > AVGC199 AND C1 <= AVGC199.1

If we want to check for both potential and actual crosses we would get:

(C > AVGC199 AND C1 <= AVGC199.1) OR (C > AVGC200 AND C1 <= AVGC200.1)

More complicated versions of formulas for potential crosses would check for the current price and tomorrow's price to be within some arbitrary margin of each other. This might be some multiple or fraction of either ATR or a moving average of absolute net changes or even something simpler like a certain percentage of price.