Member Since Aug 20, 2009 114 posts
Juan Cruz Baudino (cacus)
Jul 21 2011 at 06:03
I see that currently the monthly performance histogram (right at the bottom of the system page) is calculated in a strange way, imho.
For example some of my accounts shows that the monthly performance is calculated by (thismonth_ending_balance/initial_deposits)-previousmonth_percentage_performance.
That's why for example the first month is calculated ok: ( (ending balance / deposits ) - previous month performance )
1500/1000 - 0 = 50% performance
But the problem is from the second month and further:
2000/1000 - 50 = 50% performance
This leads to wrong monthly average performance calculus, you can see clearly it when you upload a strategy and the analysis page tells you that it has a monthly average of 1000%!!! Which is not accurate by any mean.
Since we do have the month_ending_balance (suppose we store it at a new variable called previousmonth_ending_balance) the following algorithm, relatively to the starting balance each month would yield more accurate number for the analysis:
thismonth_ending_balance/previousmonth_ending_balance = monthly performance relatively to each month's starting balance and not based on initial deposits.
1500/1000 = 50% (ok)
2000/1500 = 33% (ok)
See the difference?, to get a 50% performance on the second month the ending balance would have had to be 2250. This is what i mean to 'relative' monthly performance.
This would automatically bring a clearer and accurate monthly average calculus and also the monthly percentages would be more clear.
Hope i made it clear and hope i don't bother.
Thanks and keep up the good work!.
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