Results from screener do not match with indicator

Forums ProRealTime English forum ProScreener support Results from screener do not match with indicator

Viewing 3 posts - 1 through 3 (of 3 total)
  • #183914

    Hello,

    I have an issue with the ProScreener that I really cannot explain.

    I created a very simple screener that searches for stocks which closes above the 200 SMA and the 2-period RSI is below 15.
    The ranking is done based on the ROC with a period of 20.
    The code is the following one (most of it is generated automatically):

    While running the screener on different eod data I find out that the ranking of the screener produces false values for some of the stocks. I compared the values of ROC-20 given by the screener with the ones I see by adding the indicator in the platform.

    Here some explamples where the values matches and where not (the screener was run by using the default NASDAQ stock list):

    <place pictures here>

    Out of 16 stocks the screener found for 3 stocks the values does not match between the screener and the indicator in the platform (VIA, EMCF, PWOD).
    Out of curiosity: I did the same run also with the ROC period of 100. Here for 5 stocks the ROC values did not match (the ones above plus FUNC and SAFM).

    Can someone explain why I see different values in the screener compared to the ones I see in the platform?

    I found also some older postings from other users that have similar issues. The most commen answeres are the following ones without giving a clear answer to that issue:
    1. The screener uses only 256 bars.
    2. The data are delayed if you use a free account with eod data only; this could cause the issue.

    In my humble opinion both options do not apply to my issue, as
    1. The screener does not use an indicator that needs more than 256 bars (especially the ROC-20 should use only 20 past bars and here the values do not match with the ones I see on the indicator).
    2. Even if the data are delayed, why does it match for most of the stocks and only for some of them they don’t match? And even more: I run the screener late night after the market closes as well as on the next day. The results were exactly the same. Moreover: I see the day bars on the screen which means the data are available for that day. And the calculation of the indicator in the platform seems to be correct. But it still does not explain why for some of them the values differes from the ones the screenes provides.

    I hope somebody can tell me if this is a bug or (more likely) I’m doing something wrong even I do not see my mistake.

    #183934

    Hi,

    The Proscreener module being independant from the probuilder module, seeing candle data displayed in the evening and available for indicator doesn’t mean it’s available in real time for screener with the free eod version (which, unless it has changed recently would mean screen from end of day data can be done only after start of next trading candle).

    More over consitions c1 and c2 are simple enough to be potentially true for some consecutive candles, so it makes it likely results for many stocks be common from one day to the next. It comes down to looking at individual differences, and check if something untrue on screen and true on indicator becomes true on screen too on following day with the one-day delay applying only to screen.

    #184053

    Hello,

    thanks for the hints. I checked that by waiting for one more candle and add at the end of all indicator calculation [1] to get the results from the day before.

    Two thinks happen:

    1. I got more results; now I have 47 results, before I got 16. But this is okay as some stocks seems to have a delay (probably some smaller ones).
    2. Unfortunately the above issue is still not solved. For the very same stocks there is a missmatch between the screener and the indicator. I did not note the exact diff between screener and indicator, but for me the diff looks the same.

    Would this issue also occur when I get the payed version? I’m perfectly fine if this is only cause of the delay of the free eod data, but it seems not to be the case.

Viewing 3 posts - 1 through 3 (of 3 total)

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