I find it interesting (but not really surprising) that the EV method discussion gets directed towards tick-based volume analysis. Linnsoft's Investor/RT tool includes "Volume Breakdown" and "Cumulative Delta" capabilities for several years (and instructional videos on their site: http://www.linnsoft.com/vb) as well as courses offered by Fulcrum Trader (http://www.fulcrumtrader.com, previously active on EliteTrader.com under AMT4SWA nickname). I had some hands-on experience with system testing using VB principles in 2009 but the statistical edge using a single instrument turned out to be too slim to be of practical use for retail trading.

The VB analysis is reportedly most relevant to instruments that trade 24x7 and capture all traded volume (e.g. ES futures contract on Globex). Maybe this is where discrepancies in EV measurements produce less-than-ideal examples on a stock-by-stock basis. My own hunch (tho not proven) is that EV analysis shines due to the law of large numbers when statistics is aggregated across a large number of stocks over a period of days/weeks. In other words, if you look under a microscope, you're bound to find plenty of errors, but taken together, you get a much better signal/noise indicator.

Availability of tick-data history (unless you're a GS) is rather limited and would require considerable storage and data management efforts to carry out, compared with processing 1-min data. Saying it, if the EV method accuracy warrants it and can be translated into a non-trivial boost to EV robot performance, such effort would be quite worthwhile IMHO.

-TraderD