This would include any of the below individually or some of the below in combination:
1) UpVolume as a pct of TotalVolume
2) UpTicks as a pct of TotalTicks
3) BidSize as a pct of BidSize+AskSize
4) TradeVolume at Bid as a pct of TradeVolume At InsideAsk+TradeVolume At InsideBid (similar to Volume Delta)
Of course, I am looking at the EMini futures on a short time-frame....100 tick bars or 5 tick range bars.