Add Backtesting to the Screener
What would be really useful is the ability to run the filter on a specific dataset e.g. Finals December 2005. All that is required is the set of stocks a filter might have produced for the dataset, together with a price on the final day of the month. The user could then manually work out what to do with all the changes in ownership and get an idea of performance. I accept that running on specific dataset limits the shares that would be thrown out but I can't think of an 'easy' way to do it. What do you think?
I like the idea of forward testing but would prefer to keep my filters and their performance 'close' until they are proven to work. I guess that means a 2/3 year lag from when you make the facility available but it would surely be worth it in the end.
Test your custom screen's performance against say the last 5 years of financial data
It is easy to be wise after the event but we could, perhaps, learn from our mistakes, or triumphs, if we could see the numbers that most influenced the result.
Would it be possible to go back in time?
I have in mind the portfolio screen but with the option to show the data for an earlier date.
We discuss backtesting a bit here – http://help.stockopedia.co.uk/knowledgebase/articles/80621-can-you-add-longer-timeframe-performance-histories
Doing backtesting badly (as some sites do) is easy but the results are more harmful than anything else. Doing it well and dealing with survivorship bias etc. is much harder but we do plan to do this. Timing is uncertain though given the complexity.
See the discussion here: http://www.stockopedia.co.uk/content/seeking-safe-value-69448/?comment=4#4