Imbalance is important information but in my humble opinion you should not enter trades based on order imbalance in and of itself.
The
market delta video you watched was just highlighting the imbalance feature on their footprint charts. It is something you will also see on the
tape AND some depth of markets (i.e. Jigsaw trading tools). Since Market Delta has a great
DOM and tape I am positive they took the trade based on a confluence of information INCLUDING the imbalance.
In my experience you are going to see some sort of imbalance on most bars. The fact of the matter is NOBODY knows if the imbalance will result in a reversal until it does
reverse. All it is showing you is that there are more aggressive traders on one side of the market.
I use the imbalance on my charts but have never entered a trade solely on spotting an imbalance. I look at imbalance as a "heads up" and to monitor the trade once I get in. What I like to see is stacked imbalance (imbalance over two or three price levels).
As an example -
Lets say price has been moving up and I start to see stacked sell imbalances. This tells me that aggressive sellers are hitting the
bid. I will then watch how the limit orders react to the sellers. Are the limits absorbing the selling or are they pulling their orders? Are the offer limits firming up? Are the aggressive sellers getting anywhere? I have seen many instances where the limits hold and the result is continuation to the upside due to the aggressive sellers stopping out. When somebody has a refreshing order (aka iceberg) you are going to see a HUGE imbalance with no movement in price.
When in a trade it is nice to see stacked imbalances in the direction of your trade. If I start seeing imbalance opposing the trade it is a sign I need to tighten up the stop and be prepared to exit. I will not exit based solely on imbalance; I will watch the DOM and tape to confirm.