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<font
size=2 color=navy face=Arial>Roy<font size=2 color=navy
face=Arial>,
<font size=2 color=navy
face=Arial>Many
thanks for pulling that information together for me. I see now that you were
writing about the difference in calculated values between an Indicator and an Exploration
in MS, and how that can be corrected by forcing the exploration to use a longer
data series.
<font size=2 color=navy
face=Arial>
<font size=2 color=navy
face=Arial>My issue
is different from that. It concerns MS calculating a different value for an
indicator that incorporates Linear Regression and <font
size=2 color=navy face=Arial>Average<font size=2 color=navy
face=Arial> <font
size=2 color=navy face=Arial>True<font size=2 color=navy
face=Arial> <font
size=2 color=navy face=Arial>Range<font size=2
color=navy face=Arial> than another program (Trade Station) does. It has been suggested
to me that the other program is right, and MS gets it just a few cents wrong.
<font size=2 color=navy
face=Arial>
<font size=2 color=navy
face=Arial>Any idea
whether that would be the case, and if so, how to correct it?
<font size=2 color=navy
face=Arial>Thanks
again,
<font size=2 color=navy
face=Arial>Barry
<span
lang=EN-US >-----Original
Message-----
From: Roy Larsen
[mailto:rlarsen@xxxxxxxxxxxxxx]
Sent: <st1:date
Month="4" Day="21" Year="2003"><span lang=EN-US
>Monday, 21
April 2003<span lang=EN-US
> <st1:time
Hour="13" Minute="50"><span lang=EN-US
>1:50 PM<font
size=2 face=Tahoma>
To: equismetastock@xxxxxxxxxxxxxxx
Subject: Re: [EquisMetaStock
Group] Inaccurate Indicators
<font size=3
face="Times New Roman">
<font size=2
face="Courier New">Barry<font
size=2 face="Courier New">
Many standard MS indicators use a form of
exponential smoothing as part as
an integral part of the indicator. Exponential
moving averages don't "drop
off" old data in the same way that Simple
moving averages do, so a part of
ALL historical data available to the EMA is
included in it. With each new
bar some of the new data is added, this replacing
a proportion of the old
data, but not ALL. The retained data still has
SOME of all previous data.
Addmittedly the oldest data is just a very small
fraction of the current EMA
value, but the absence of old retained data in an
exploration that only
requires "minimum" periods can cause a
significant variation in value than
the same EMA observed on a chart.
Suppose your exploration uses "minimum"
periods, and the longest period
indicator isa a 14 period EMA. Now if your charts
are set to load 1000 bars
then then a 14 period EMA will calculate using
1000 bars of data. However
the exploration will only be forced to use 14 bars
of data. In such a
situation the chart EMA is much more accurate. Put
another way, the
exploration EMA could be off by several percent.
The easiest solution to this problem is to
"force" all explorations to scan
at least 5 times the number of periods of the
longest EMA affected
indicator. I seldom use less than 400 bars in an
exploration, and never use
"minimum" unless I am testing for the
very situation discussed here.
What you must realize is that many indicators
include EMA, Wilders, or some
other form of exponential smoothing as part of the
internal calculation.
The following post I made at StockCentral some
time ago may also be helpful.
See <a
href="">http://www.stockcentral.com.au/forum/machine/Forum32/HTML/000414.html
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