big discrepancy

[bertg 10]

Folks,

 

I use stockcharts.com and the data from my broker, Thinkorwsim.

 

Why such a big discrepancy in the 200 EMAs between the two charts (286.07 vs. 260.42)? Any ideas? I am always amazed at how almost no two charts are alike.

 

Volume in charts from Sierra with TransAct data is always different from TS, and so on...

 

Regards,

Bert

[Infinity_Tom 10]

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Tom

[fifty2aces 10]

Take a look at the new Infinity AT V3

 

AT V3 is the latest generation of the platform in an evolving industry with an insatiable appetite for advanced technology. Speed, speed and more speed.

 

Without a doubt the new V3 price engine is among the fastest and most efficient data feed in the industry.

 

Designed to capture the maximum amount of tick data, AT V3 will profide a FREE data feed to premium charting platforms like Linnsoft & MarketDelta.

 

Demo the latest and greatest today.

 

Best regards,

 

Tom

 

That doesn't really answer the question though, does it?

 

 

Bert, one reason EMAs could vary would be if they are calculated by close values, since these are dependant on where the bar starts. Both data feeds could be perfectly accurate, but since close values are merely price sampled at fixed intervals (whether time, tick, or volume based), they can vary depending where the sampling starts.

 

Similarly, the EMAs may be based off different values - one may be calculated using close valuesof each bar, the other might be (High+Low)/2 or (High+Low+Close)/3.

 

Another potential reason could be that there is more than one way of calcualting an EMA:

 

http://en.wikipedia.org/wiki/Exponential_moving_average#Exponential_moving_average

 

Also, make sure that your data actually goes back enough bars - trying to calculate a 200EMA with only 100 bars in the chart will obviously not work properly.

Edited August 25, 2008 by fifty2aces

[Guest forsearch]

Folks,

 

I use stockcharts.com and the data from my broker, Thinkorwsim.

 

Why such a big discrepancy in the 200 EMAs between the two charts (286.07 vs. 260.42)? Any ideas? I am always amazed at how almost no two charts are alike.

 

Volume in charts from Sierra with TransAct data is always different from TS, and so on...

 

Regards,

Bert

 

Bert,

 

FiftyAces is correct. Long-term EMAs require mucho data to get the EMA calculated correctly. Especially 200 EMA. If your charting application is not backfilling enough data from history to plot an accurate calculation of the EMA, you'll get an approximation, which I suspect is the case here.

 

In the case of Transact/Infinity, you need to make sure that whatever charting you are using (Sierra, Investor R/T, Ensign, etc.) is drawing as much history for a comprehensive backfill as possible.

 

For example, when using the free charting from Open E Cry on their OEC Trader platform, I experience the same thing on a regular basis, especially with tick or volume based charts. Reloading or refreshing history to provide a proper backfill invariably causes a "Too Many History Requests" error, forcing you to logoff and log back on OEC. (This same error occurs even when not reloading or refreshing data, but merely switching charts between different symbols. Go figure).