Todays Trading, page-25

there is a gap theory. however there best thing to think about with gaps is that they act like a whirlpool. get close enough and u could get sucked in. in regards to when a gap might not get closed - it depends on the TA at the type. there is no hard and fast rule that a gap has to filled. it is a probability game. history shows that in general there will be attempts to fill it. now do I purely rely on gap theories - No because one could miss out a
on a good run in the interim. so to answer your question it is an unknown and the further u get away from.the gap the better and all ta needs to be viewed with multiple indicators.