Hi,
I have a very strange problem. I plot a 50 and 200 EMA on a weekly chart. When i try and use these values in a screener, the values are different!
On my chart, a UK stock AAIF, the 50 and 200 EMA are: 203.3 and 209.7 but the return values from the screener are: 199.2 and 191.4.
I have checked the same type of MA is being used (Exponential on both the chart and the screener) and i’ve also cross checked the values with the previous week but they don’t correlate.
Can anyone help at all please?
Thanks.
JSParticipant
Veteran
Hi Ollie,
When you use the free version of PRT, the screener is always 1 bar behind…
When you use the complete version, the screener has a maximum memory of 256 bars, which is insufficient to properly calculate the EMA200…
If you use the Premium version, you will have 1024 bars of memory, and this should be enough…
Hi,
Thanks for taking the time to reply.
I am only interested in the latest value so i’d have thought the 256 limitation doesn’t impact the most recent 56 bars unless there is something funky with the EMA calculation?
I am using PRT through a UK broker (IG Index). I think this is the complete version as i can get intra-day prices but i am not 100% sure.
Even if i look 1 bar behind the values don’t make sense. I’ll switch to simple MAs and see whether that suffers the same problem.
I appreciate your help very much, thanks.
JSParticipant
Veteran
There is indeed something funky about the calculation of an exponential average, namely that it uses much more history, two to three times more, than a normal average…
Properly calculating an EMA200 with a history of 256 bars is not going to work…
I have changed the MA from exponential to simple in the screener and it works as expected for the 50 and 200.
What a strange issue, i’d never have worked that out without your help.
Thanks.
JSParticipant
Veteran
An exponential average weighs the current prices more heavily than the previous ones, making it react faster than an ordinary average.
Because the exponential average also works with previously calculated rates, they will also have to be “remembered”, hence the use of more memory…
