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Hi Keith, sorry I don't do portfolio testing so
have no idea...
Steve
----- Original Message -----
Sent: Wednesday, December 02, 2009 10:45
PM
Subject: Re: [amibroker] Re: What's a
good k ratio,and thoughts on when k ratio clashes with MDD and Shar
Mike and Steve -- The limiting of
range to that of the data available, rather than to settings in AA, is less
than obvious from reading the User's Guide.
When doing portfolio
testing, is the range on equity by equity basis, or from the first bar of any
equity to the last bar of any equity? (I can't even imagine how one
would either calculate or interpret the results doing it equity by
equity).
BTW, I believe your answers highlight my request for
"AFL formulas to produce results equivalent to
those shown in AB back tester analysis"
I am familiar with Fred's
IO portfolio.afl, and will indeed examine it more closely. Good
suggestion.
Thank you. -- Keith
Mike wrote:
Pretty much amounts to the same thing since there are generally 252
bars per 365 days. But, the earlier sample could easily be modified to
instead use:
first = LastValue(ValueWhen(Status("firstb
arinrange"), DaysSince1900()));
last = LastValue(ValueWhen(Status("lastbarinrange"),
DaysSince1900()));
... CAR = 100 *
((bo.Equity/bo.InitialEquity) ^ (365/(last - first +
1)) - 1); <
/font>
Mike
--- In amibroker@xxxxxxxxxps.com, "Steve
Dugas" <sjdugas@xxx> wrote: > > Hi
- For CAR, the user guide gives the formula used by AB... > >
AmiBroker is one of the few programs that calculates annual returns
correctly and will give you correct value of 20% as shown in the example
above. The formula that AmiBroker uses for annual return calculation is as
follows: > > correctly_annualized_perc_return = 100% * (
(final_value/initial_value) ^ ( 365 / days_in_test ) - 1 ) >
> ----- Original Message ----- > > From: Mike >
To: amibroker@xxxxxxxxxps.com > Sent: Tuesday, December 01, 2009
5:01 PM > Subject: [amibroker] Re: What's a good k ratio,and thoughts
on when k ratio clashes with MDD and Shar > > > >
> Keith, > > > Change the granularity of your
formula to be on a bar basis, as opposed to an annual basis, and you should
come out with a value very close to what AB produces. > >
> e.g. > > > SetCustomBacktestProc("");
> > if (Status("action") == actionPortfolio) { >
first = LastValue(ValueWhen(Status("firstbarinrange"),
BarIndex())); > last =
LastValue(ValueWhen(Status("lastbarinrange"),
BarIndex())); > bo = GetBacktesterObject(); >
> bo.Backtest(); > > CAR = 100 *
((bo.Equity/bo.InitialEquity) ^ (252 / (last - first + 1)) - 1);
> > bo.AddCustomMetric("MyCAR", CAR); > } >
> > I believe that the information for K-Ratio is out of date.
The formula has been revised. I seem to recall the author suggesting that a
value of 0.5 was good. Howard has suggested that 0.15 was good. >
> > Note that the metrics you were comparing dealt with return
without regard for how that return was achieved. K-Ratio measures the
consistency of the return. So, it is not unusual to have strong CAR/MDD with
poor K-Ratio. A couple of big gains would improve the former while hurting
the latter. > > > I seem to recall a posting in this
forum offering many of the calculations that you're asking for. Otherwise,
you can try looking at the Portfolio.afl of IO since it displays many of the
same values. > > > Mike > > --- In
amibroker@xxxxxxxxxps.com, Keith McCombs kmccombs@ wrote: >
> > > Mike -- > > The tooltip (which I must admit I was
unaware of), unfortunately, > > provides no more information than
the "AmiBroker User's Gu ide" (which I > > referred to in my
previous posting). > > > > Using your suggestion of
Googling the metrics, I Googled CAR, and came > > up with the
following link: > > http://www.investorglossary.com/compound-annual-return.htm#rate_definition >
> resulting in the definition, "The formula for the compound annual
return > > is ((Ending Value) /(Beginning Value))^(1/Number of
years)-1." > > > > I just ran a portfolio backtest for a
strategy from 10/26/07 to > > 10/25/09, a period of 2years. The
results were: > > Initial capital 100000.00 100000.00
100000.00 > > Ending capital 134224.01 134224.01 100000.00 >
> Net Profit 34224.01 34224.01 0.00 > > Net Profit % 34.22 %
34.22 % 0.00 % > > Exposure % 2.70 % 2.70 % 0.00 % > > Net
Risk Adjusted Return % 1268.77 % 1268.77 % N/A> > Annual
Return % 19.79 % 19.79 % 0.00 % > > Risk Adjusted Return % 733.63 %
733.63 % N/A > > > > > > Note that the net
profit over the two year period is 34.22% and the > > Annual
Return is shown as 19.79%. However if one calculates the Annual >
> Return using net profit and the formula above, > >
1.3422401^.5 -1 = 15.855%. > > > > The AB User's Guide
suggests that a good system might have the following > >
characteristics: > > "CAR/MaxDD - Compound Annual % Return divided
by Max. system % drawdown. > > Good if bigger than 2". >
> > > "Sharpe Ratio of trades - Measure of risk adjusted return
of investment. > > Above 1.0 is good, more than 2.0 is very
good." > > > > "K-Ratio - Detects inconsistency in
returns. Should be 1.0 or more." > > > > The s trategy
tested above showed the following: > > MDD = -8.02% > >
CAR/MDD = 2.47 > > RRR = 4.32 > > Sharpe = 5.27 >
> K-Ratio =0.0051 (seems rather inconsistent with others) > >
> > I have back tested many profitable, low risk systems over the
years, and > > do not recall ever seeing a K-Ratio greater than
1.0. > > > > So, I'd still like to have AFL formulas
to produce results equivalent to > > those shown in AB back tester
analysis. > > > > And, BTW, does AB calculate MDD
from High/Low bars or from equity curve > > based on closes. I
suspect the latter, but don't really know. > > > > Thank
you. > > -- Keith > > > > > > Mike
wrote: > > > > > > > > > For a textual
description, generate a backtest report and the n hover > > >
your mouse over any metric name. The tooltip will provide a > >
> description of the metric. For most, a mathematical explanation can be
> > > found via google. > > > > > >
Mike > > > > > > --- In
amibroker@xxxxxxxxxps.com <mailto:amibroker%40yahoogroups.com>,
> > > "Potato Soup" potatosoupz@ wrote: > > >
> > > > > Yes, I still don't have an explanation for what
car is. And all the > > > others I listed. > > >
> > > > > -----Original Message----- > > >
> From: Keith McCombs kmccombs@ > > > > Date: Mon, 30 Nov
2009 14:05:23 > > > > To: amibroker@xxxxxxxxxps.com
<mailto:amibroker%40yahoogroups.com>> >
> > > Subject: Re: [amibroker] What's a good k ratio, > >
> > and thoughts on when k ratio clashes with MDD and Sharpe? >
> > > > > > > One thing that I would find most
helpful, as far as performance metrics > > > > are concerned,
is a precise definition of each metric in "AmiBroker > > > >
User's Guide" (page 156 for v5.20), including AFL formulas to
produce > > > > results equivalent to those produced by AB
back tester analysis. > > > > > > > > --
Keith > > > > > > > > Howard B wrote: >
> > > > > > > > > > > > > >
Hi PS -- > > > > > > > > > > One way to
get a feeling for values for metrics and objective > > > >
> functions is run an optimization, giving you a range of results.
If > > > > > necessary, peek into the future so you are
certain to get some really > > > > > good results. >
> > > > > > > > > Look through the list of
results, pick some individual results with a > > > > >
variety of values for the metrics you want to learn about. > > >
> > > > > > > Set the default value of the optimized
variables to the specific > > > > > values you
chose. > > > > > > > > > > Run a single
backtest. Plot the equity curve. > > > > > > >
> > > When you have done a few of these and have a feeling for
the > > > > > characteristics of the systems you would
like to trade, print out the > > > > > plot of the equity
curves and write the values of the metrics and > > > > >
objective functions on the printout. > > > > &g
t; > > > > > ----------------------- >
> > > > > > > > > Your question about
interpretation. > > > > > > > > > > My
preference is for objective functions that reward equity growth >
> > and > > > > > penalize drawdown. CAR/MDD,
RAR/MDD, RRR, Recovery Factor, K-Ratio, > > > > > Ulcer
Performance Index, and Sharpe Ratio all do that. In all of > > >
> > these cases, larger values are better. > > > >
> > > > > > The important results are the out-of-sample
results. We are looking > > > > > for logic and parameter
values that not only perform well in-sample, > > > > > but
that also perform well out-of-sample. > > > > > >
> > > > When you run walk forward tests, you will find that s
ome objective > > > > > functions give high rank to
alternatives that do tend to perform well > > > > >
out-of-sample, while other objective functions select alternatives >
> > > > that often do not perform well out-of-sample. You will
need to run > > > > > some of your own tests to get a
feeling for how these work on your > > > > > trading
systems. > > > > > > > > > > My
experience is that using net profit is usually a poor objective > >
> > > function, although it is the default (and often the only)
selection > > > > > for some trading systems development
platforms other than AmiBroker. > > > > > > >
> > > Fund managers are evaluated on the Sharpe Ratio of their
performance. > > > > > My experience is that systems
selected using Sharpe R atio tend to > > > > > perform
poorly out-of-sample. > > > > > > > > >
> Standard Error is a measurement of the smoothness of the equity
line > > > > > -- smaller values are better. But
optimizing to minimize standard > > > > > error alone may
give high ranks to systems that have trading > > > > >
characteristics that you do not want. For example, if you have the >
> > > > options set so that the equity earns interest when ever
it is not > > > in a > > > > > position, then
using standard error will reward alternatives that > > >
stay > > > > > in cash and trade infrequently. >
> > > > > > > > >
------------------------ > > > > > > >
> > > One of the very valuable features of AmiBr oker is the
capability for > > > > > the system developer to create
whatever objective function he or she > > > > > wants to
use. It does not have to be limited to those that are > > > >
> distributed with AmiBroker and appear in the list of metrics.
You > > > > > might want to combine metrics -- for example
to reward alternatives > > > > > whose trading frequency
suits your preferences, while also rewarding > > > > >
equity growth and penalizing drawdown. > > > > > >
> > > > Thanks, > > > > > Howard > >
> > > > > > > > > > > >
> > > > > > > > > > > On Sat, Nov 28,
2009 at 11:33 PM, potatosoupz potatosoupz@ > > > > > <mailto:potatosoupz@> wrote: >
> > > > > > > > > > > > >
> > > > > > I don't see any good definitions for the
metrics below. I am > > > > > familiar of course with
Sharpe, and Ulcer Index. I'm finding it a > > > > > bit
hard to reconcile the differences. How would you reconcile a > >
> > > backtest that has a max draw down % that is smaller than
it's > > > > > profit %, a low ulcer index, a high Sharpe,
but a very low k ratio > > > > > (< .05)? > >
> > > > > > > > Ulcer Index in my mind is one of
the best metrics outside of a > > > > > much deeper
quantitative treatment of things. Thoughts? > > > >
> > > > > > CAR/MDD ? > > > > >
RAR/MDD ? > > > > > Payoff Ratio ? > > > >
> Standard Error ? & gt; > > > > RRR ? > >
> > > Recovery Factor ? > > > > > > >
> > > > > > > > > > > > >
> > > > > > > >
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