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Re: [amibroker] Trouble with FT data



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I thought you've said an intraday eSignal database had both intraday 
and EOD data (and I've had "Force mixed EOD/Intraday mode" set in the 
Configure settings and "Allow mixed EOD/Intraday data" (and Use 
Exchange time) set in my Intraday settings) so I assumed the EOD data 
would be the same "cleaned up"/true/resolved OHLC I'd get if I only 
requested eSignal daily data. If the EOD data mixed in with the 
intraday data isn't the "cleaned up" OHLC as reported by all data 
providers, what is it?

Does this mean that if I want to use the true daily open (within the 
120 day intraday range) in my backtests, I need to use an EOD 
database (eSignal or Yahoo or ... )? At least I wouldn't get 
something from the last hour (as it appears is happening now), right?

My data base settings have always been set to show "Show day session 
only" and start time = 9:30 and end = 16:00.

I'll do some more experimentation to see if I can make some sense out 
of it.

Dan

--- In amibroker@xxxxxxxxxxxxxxx, "Tomasz Janeczko" <amibroker@xxxx> 
wrote:
> Hello,
> 
> See this post:
> http://finance.groups.yahoo.com/group/amibroker/message/63015
> 
> When using eSignal mixed mode, last 120 days are filled with 
intraday data and when you switch
> to "Daily" intraval those bars are generated by time-compression of 
intraday
> bars. Exact results of time compression depends whenever you have
> pre/after hours data viewing turned on or off and depends on
> your start/end time settings in File->Database Settings->Intraday 
Settings.
> 
> Best regards,
> Tomasz Janeczko
> amibroker.com
> ----- Original Message ----- 
> From: "danielwardadams" <danielwardadams@xxxx>
> To: <amibroker@xxxxxxxxxxxxxxx>
> Sent: Friday, July 23, 2004 9:18 PM
> Subject: [amibroker] Re: Simple question
> 
> 
> > It appears that backtesting against both Yahoo and eSignal 
databases 
> > outside the 120 eSignal intraday range gives results that are 
very 
> > similar (but not identical). Outside the 120 day range, I also 
see 
> > the OHLC are the same on the charts for both databases (spot 
checking 
> > only).
> > 
> > Within the 120 range, however, the OHLC show differently within 
the 
> > daily charts and it appears the eSignal values might be taken 
from 
> > sometime in the last hour of trading (?). It is within the 120 
range 
> > that the backtest buy and sell points start to diverge.
> > 
> > I could probably dig deeper but I have to leave for an 
appointment.
> > 
> > Dan
> > 
> > 
> > 
> > Once I get inside the intraday range, 
> > 
> > --- In amibroker@xxxxxxxxxxxxxxx, "ed" <ed2000nl@xxxx> wrote:
> > > you can simply test what the problem could be. Do a backtest 
over a 
> > limited period and compare the trades. 
> > > 
> > > One thing that could have gone wrong is that you pad with the 
same 
> > symbol (see AA, settings, Pad and align data). 
> > > 
> > > But in general to find what the problem could be you have to 
start 
> > comparing the trades you get for the different databases and go 
from 
> > there,
> > > 
> > > rgds, Ed
> > >   ----- Original Message ----- 
> > >   From: danielwardadams 
> > >   To: amibroker@xxxxxxxxxxxxxxx 
> > >   Sent: Friday, July 23, 2004 5:39 PM
> > >   Subject: [amibroker] Re: Simple question
> > > 
> > > 
> > >   Does anybody else have problems getting comparable results 
doing 
> > >   daily backtests of the same stocks with the same strategy, 
> > period, 
> > >   and settings using the Yahoo and eSignal databases?
> > > 
> > >   I just tried another period (365 days) and although the 
number of 
> > >   trades was comparable (407 versus 443), the annual returns 
aren't 
> > >   even close (212.97% versus 72.09%).
> > > 
> > >   Would somebody please shed some light on these descrepancies.
> > > 
> > >   Dan
> > > 
> > >   --- In amibroker@xxxxxxxxxxxxxxx, "danielwardadams" 
> > >   <danielwardadams@xxxx> wrote:
> > >   > If I backtest the same portfolio of (approx 50) stocks with 
> > exactly 
> > >   > the same strategy and settings over the same period of 
time, 
> > >   > shouldn't I expect fairly comparable results with both the 
> > Yahoo 
> > >   and 
> > >   > eSignal EOD databases?
> > >   > 
> > >   > I would expect them to be close (acknowledging things like 
> > splits 
> > >   and 
> > >   > data errors might be handled differently), but my results 
> > aren't 
> > >   even 
> > >   > close.
> > >   > 
> > >   > One test from August 1999 to date gave the following 
results.
> > >   > 
> > >   > Yahoo:   Annual return = 66.71%, number of trades = 2287.
> > >   > eSignal: Annual return = 52.05%, number of trades = 3977.
> > >   > 
> > >   > Although the eSignal data costs $$$, frankly I think I 
trust 
> > the 
> > >   > Yahoo data more. I've reported problems with the 
determinism of 
> > the 
> > >   > eSignal data before and haven't gotten any satisfactory 
> > feedback. 
> > >   > (Example: Not forcing backfill on all stocks to the same 
date 
> > even 
> > >   > though the data does exist). 
> > >   > 
> > >   > Which data should I believe? Or, maybe, are both sets of 
data 
> > okay 
> > >   > and it's a matter of the backtest code not working 
properly? 
> > >   > Backtesting is the ONLY reason I want to use Amibroker but 
I'm 
> > >   about 
> > >   > ready to give up on it.
> > >   > 
> > >   > I'd be interested in anybody else's experiences on either 
data 
> > >   > reliability or backtest reliability/determinism.
> > >   > 
> > >   > Dan
> > > 
> > > 
> > > 
> > >   Check AmiBroker web page at:
> > >   http://www.amibroker.com/
> > > 
> > >   Check group FAQ at: 
> > http://groups.yahoo.com/group/amibroker/files/groupfaq.html 
> > > 
> > > 
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