|
PureBytes Links
Trading Reference Links
|
Chuck, aka Dataman, thanks for all your past posts
regarding the importance of good data. Based on your previous posts,
and my rudimentary research, it is my opinion that CSI's Unfair
Advantage EOD data is probably the best EOD data
available. I urge all of you to read the lower section of
this post entitled THE IMPORTANCE OF DATA ACCURACY. One final note of caution.
The Yahoo website states that Yahoo historical data comes from CSI,
however CSI responded to one of my email's and stated that
Yahoo's Historical data does NOT come from CSI. Later
Ron D
<BLOCKQUOTE
>
----- Original Message -----
<DIV
>From:
<A title=chuck_rademacher@xxxxxxxxxx
href="">Chuck Rademacher
To: <A title=amibroker@xxxxxxxxxxxxxxx
href="">amibroker@xxxxxxxxxxxxxxx
Sent: Wednesday, September 10, 2003 6:06
AM
Subject: RE: [amibroker] EOD DATA
ACCURACY
<FONT face=Arial color=#0000ff
size=2>Ron,
<FONT face=Arial color=#0000ff
size=2>
You
can download data from CSI ten minutes after the market closes, if you want
to. Of course, it won't contain all of the closing prices and many
prices will be wrong.
<FONT face=Arial color=#0000ff
size=2>
You
can continue to download for the next three hours and each download will
update previously downloaded prices.
<FONT face=Arial color=#0000ff
size=2>
<FONT face=Arial color=#0000ff
size=2>After four hours, corrections and additions are still being
done. The data at that point should be about 98%
correct.
<FONT face=Arial color=#0000ff
size=2>
You
can continue to download right through the night and each update may have more
changes.
<FONT face=Arial color=#0000ff
size=2>
A
point in time occurs when you start downloading the next day's
data. However, corrections can (and do) continue basically
forever. Today's download, for instance, contained more than 100
changes affecting U.S. stock prices more than ten years ago. Most of
those corrections, were arising from errors reported by
me.
<FONT face=Arial color=#0000ff
size=2>
The
number of errors and the number of corrections is no reflection on CSI.
On the contrary, this is where (IMO) CSI shines. They don't give
up on the data... ever.
<BLOCKQUOTE
>
<FONT face=Arial
size=2>============================================================================
The Importance of data accuracy.
The Futures study clearly demonstrates that technical analysis requires
accurate data. In the study, S&P 500 data from CSI, Omega Research, and
Bridge were used on the same simple breakout system with strikingly
different results. The profit scenario varied from 20% to much more than
100% over the full period of study. This should offer substantial proof that
the derived effects of a flawed database can lead to a useless result and a
wasted effort because parameter settings determined from flawed data cannot
be expected to work with the same efficiency in the market on which they
will be applied. Unfair Advantage's software and database are designed so
that every user is equipped with exactly the same data set at all times,
forcing any common analytical tool that is derived from past information to
produce equivalent results on different machines.
Building a trading model based upon flawed past data
is certain to degrade system effectiveness into the future. This truth,
learned decades ago by CSI's founder Bob Pelletier, is the driving force
behind CSI's policies. Before CSI was incorporated in 1970, studies done by
Pelletier, a General Electric mathematician at that time, were inevitably
tripped up by some obscure error that dominated parameter settings and
falsely influenced the outcome of simulation exercises by forcing undeserved
profits from the flawed data. It may seem that a small error here or there
would not be important, but that was not the result in the work. Experiences
like this made it abundantly clear that errors must be forbidden if any
fruitful benefit was to be derived from hindsight testing.
Several of the data vendors included in the study are
either allied with or directly tied to very expensive analysis programs, but
they are not necessarily the required data sources. Although CSI is
explicitly excluded from the data download screens and menus of most of
those programs, discriminating users of the industry's most powerful
software tools still come to CSI for data. They know that it is pure folly
to accept the suggestion that an average data firm can deliver the accuracy
needed to create an exceptional trading system. Now that the importance of
data accuracy has been revealed, perhaps even more traders will come
directly to CSI, whether or not their software producer steers them in that
direction. Software companies with whom CSI data products are compatible
include: Equis Int'l (MetaStock®), Omega Research, Windows on Wall Street,
ProfiTaker and many others. Send BUG REPORTS to
bugs@xxxxxxxxxxxxxSend SUGGESTIONS to
suggest@xxxxxxxxxxxxx-----------------------------------------Post
AmiQuote-related messages ONLY to: amiquote@xxxxxxxxxxxxxxx (Web page:
<A
href="">http://groups.yahoo.com/group/amiquote/messages/)--------------------------------------------Check
group FAQ at: <A
href="">http://groups.yahoo.com/group/amibroker/files/groupfaq.html
Your use of Yahoo! Groups is subject to the <A
href="">Yahoo! Terms of Service.
Send
BUG REPORTS to bugs@xxxxxxxxxxxxxSend SUGGESTIONS to
suggest@xxxxxxxxxxxxx-----------------------------------------Post
AmiQuote-related messages ONLY to: amiquote@xxxxxxxxxxxxxxx (Web page: <A
href="">http://groups.yahoo.com/group/amiquote/messages/)--------------------------------------------Check
group FAQ at: <A
href="">http://groups.yahoo.com/group/amibroker/files/groupfaq.html
Your use of Yahoo! Groups is subject to the <A
href="">Yahoo! Terms of Service.
Yahoo! Groups Sponsor
ADVERTISEMENT
Send BUG REPORTS to bugs@xxxxxxxxxxxxx
Send SUGGESTIONS to suggest@xxxxxxxxxxxxx
-----------------------------------------
Post AmiQuote-related messages ONLY to: amiquote@xxxxxxxxxxxxxxx
(Web page: http://groups.yahoo.com/group/amiquote/messages/)
--------------------------------------------
Check group FAQ at: http://groups.yahoo.com/group/amibroker/files/groupfaq.html
Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
|