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At 12:28 AM +0100 10/9/97, Ian Brant wrote:
>Hi to all
>
>I use Dial Data via the internet and have not yet had a problem getting
>data, usually seem to get through 1st time
>- BUT - as to the accuracy?
>- I have not yet compared the data - but I do recall reading something
>relating to the different data suppliers (and variations in data) being
>affected by whether the data includes night sessions aswell as the day
>sessions.
>
>Does anyone have any information on this as I am considering changing to
>another supplier but don't know where to look? As a supercharts user I find
>the Omega Downloader is easy to use, but SC will read ASCII aswell as
>Metastock and so DD is not the only choice.
>
>Any info would be greatly appreciated.
I use Dial Data for end-of-day data with TradeStation mostly because it
integrates seamlessly with the quarterly CD ROM database Omega Research
provides and automatically accounts for stock splits. I download data on
about 10,000 stocks and indices each night.
In theory, the data in available after soon after the market closes but
downloading before about 7pm is a waste of time because of errors. There
are still errors at 7pm but if you are only gathering data of a hundred or
so stocks, the probability of error by then is pretty small.
By about 11pm, most of the obvious errors are fixed but there still are
some in some stocks, particularly around the time of splits. I usually set
up TradeStation to automatically download all data in the middle of the
night.
It speeds things up greatly if you disable downloads of symbols that are no
longer active. Otherwise, it requests all old missing data on the dead
symbols which takes a lot of download time. You have to do this manually,
unfortunately. You can tell which symbols are dead from the download log or
by looking for those that have no recent data in the Downloader security
list and "unmarking" them.
When my filter finds a stock that I might like to trade, I look at the
chart for obvious errors. Most errors are very obvious on a chart. The
usual error is a missing split or a low that is far too low, etc. The same
error is often present in my BMI data so I think it is the result of a bad
tick sometime during the day.
If there are errors on the data for a stock, I delete all the data for that
stock and then download it all again. This downloads all the days since the
last quarterly CD ROM update. This is usually correct.
If someone knows of a better process I would appreciate hearing about it.
Bob Fulks
--
Bob Fulks
bfulks@xxxxxxxxxxx
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