Friday, October 09, 2009

The Market Sneezes, but Trade Ideas Never Catches a Cold: Data Variances

Editor's Note: The following post is from our Chief Technical Officer, Philip Smolen. In it he points to a rather frequent occurrence of the data inconsistencies that plague the tape and which, if left unchecked or not addressed, can seriously affect real-time sensitive tools like Trade Ideas.

Fortunately for us and for those of you who are subscribers, our team at Trade Ideas works tirelessly and with great precision to engineer such errant data out of our systems - as they happen.

Here's a peek behind the kimono . . .


I was looking at a suspicious price. Our primary data feed had a questionable price. When I checked other data feeds, they disagreed with each other. Here are three free examples. Look at the price of the open.

http://www.google.com/finance?q=ntap







http://finance.yahoo.com/q?s=ntap
http://moneycentral.msn.com/detail/stock_quote?Symbol=ntap&getquote=Get+Quote







This, and variations on this, happen a lot. People don't always realize it. If they hurry, they can see this example for themselves.

We also have a video tutorial highlighting this issue.

video

http://www.trade-ideas.com/VideoHelp/Menu.html?video=Configuration%20Window%3A%20Bad%20Market%20Data.

A lot of people try to be very precise. At one price they buy, at a penny less they don't. Some people scour the charts, and get excited when we don't match exactly to what they were expecting. Here's the reality check. Here's one I just happened to run into. I'm sure if I spent the time I could find a lot more. If you deal with market data, you have to understand the limits.


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