Quote from bolter:
paul,
One point of clarification from whisters post for those not familiar with tick data. Data vendors supply tick data in a format such as:
date, time, price traded, volume, bid, ask
with 1 record for each "trade".
So by examining the price traded relative to the prevailing bid and ask one can infer that the trade took place at the bid, the ask, or somewhere in between.
bolter
Quote from ticktrade:
I'd like to say thanks to all the excellent posts, sharing some great ideas and info about MD/time sales....comparing the >99 to the <5 lots on the es was a great idea and very helpful. Going back over about 10 days I found several times the <5 crowd diverged from price at the right time but once price went their way they seemed to fade it and go back to being wrong. For the most part the >99 was a better bunch to follow as most of you implied it would be. I've been plotting the accum. delta of >99, drawing channels and watching for breakouts.
http://www.charthub.com/images/2006/10/30/2_mintest.png
This chart shows a false break this afternoon where the <5 crowd was doing the right thing. I lost a couple ticks before I figured out it wasn't working so reversed to the previous vol based POC. Hoping someone can comment on the situation. May just be one of those things, nothing will always be right. Playing the breakouts has worked nicely lately though.
Wish I had something to offer this crowd, sure am getting a better grasp of things through all the informative posts.
The morning trade mentioned in a previous post continues to work. Using a 1 min chart and using the open vs. vol POC of previous day relationship. I enter on first delta surge away from the POC. Usually a reading of +-1500 to 2000 on a 1 min bar.
Price poked into the vol POC, almost filling the gap before the delta got me in short. Haven't done this long, usually enter this trade in the first few minutes.

I believe you are correct, although I'll confirm this with Chad. It's not that they don't have any significance but it is impossible to infer whether it was likely a buy or sell transaction. On a liquid market with a decent tick size (eg: ES) the spread will be a fairly consistent 1 tick, so this will represent a small proportion of the total volume. On thinner markets, or markets with a smaller tick, obviously it could be a much greater proportion of the total volume. I suspect it could have a material impact on MD output, but I have no evidence. From my experience however, I find MD is less useful on these types of markets.I assume that trades which happen in between the prevailing bid, ask are not recorded to the delta and are viewed as not having any MD significance?
Quote from bolter:
paul,
I believe you are correct, although I'll confirm this with Chad. It's not that they don't have any significance but it is impossible to infer whether it was likely a buy or sell transaction. On a liquid market with a decent tick size (eg: ES) the spread will be a fairly consistent 1 tick, so this will represent a small proportion of the total volume. On thinner markets, or markets with a smaller tick, obviously it could be a much greater proportion of the total volume. I suspect it could have a material impact on MD output, but I have no evidence. From my experience however, I find MD is less useful on these types of markets.
bolter
Quote from bolter:
dcraig,
Great research. That's the sort of stuff you instinctively know to be the case but never actually get around to proving it or indeed capturing the stats. Well done - thanks for sharing that with us.
All the best,
bolter