Is Back-Testing possible and how about a 'Wayback Machine' ?

30th Jan '20 by whatisgood

12 comments 1550 reads

I'm on the 14 day trial and like most of the site but am I right in thinking that you can't back-test anything?

I realise the 'since inception' growth rates are shown against the common screeners, but if you can't see how that performance was actually made it doesn't help very much.

I was hoping to be able to see which stocks are chosen from any custom or popular screener applied to the past. That ability would be very powerful as you could actually look further on in time and analyse the individual stocks that made up a screener's performance.

Q. "What were the actual winners in that screener's performance?"

I think the best and most versatile way to do this would be if you could choose a 'Site Date' from the past and you would then be presented with the Stockopedia site EXACTLY as it was on that day with all the same screener functionality etc.

If daily data has been kept or can be sourced then it should be relatively easy to implement too shouldn't it?

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HumourMe

30th Jan '20

What you describe is desirable . You may wish to comment here https://portal.productboard.com/vjasivnb3rvsgtbmqy5qnar8/tabs/5-in-consideration The old site did implement this in a limited way for the guru screens, however, not in an easy to use way (it was by share over time, rather than portfolio at a point in time). I'd like to be able to screen 'in the past' and get price look forward columns.

whatisgood

Thanks - have put the idea up there.

31st Jan '20

It isn't visible yet unfortunately.

I suspect it will be reviewed and 'folded in' to the existing back testing workflow.

One issue with the prior site suggestion mechanism was a proliferation of similar suggestions scattered through the system. And the spam.

I'm sure that the new suggestion scheme has been set up to better control these aspects.

Edward Croft

"I think the best and most versatile way to do this would be if you could choose a 'Site Date' from the past and you would then be presented with the Stockopedia site EXACTLY as it was on that day with all the same screener functionality etc."

Ah - you want a time machine. Me too.

Do remember that Rome wasn't built in a day and that time machines are tricky things to build.

Sure, depending on how the site is setup I'm sure it could be difficult to do, but I think it would be a major upgrade to the site's capabilities and its attractiveness to customers.

In essence all you would be doing is showing yesterday's site today.

dmjram

Bit more complex than that.
Results are announced and the price reacts immediately.
Those results aren't reflected in the site data for a few days/weeks.
Which means you need to track the date of results vs the date of site data update and incorporate in to the backtesting.
Hence the Point in Time dbases are premium products.
Personally I'd love to have the date of results/announcements shown on the charts as a first step to implementing this.

Macro

A good end-to-end system that includes back-testing and automated portfolios is Vectorvest.

No systems are perfect. Vectorvest might be stronger on backtesting and automation - but Stockopedia is probably stronger in financial analysis.

One approach woud be to combine both. Perform a strong financial analysis screen on Stockopedia at some past date (using Ed's time machine), export that watchlist of candidate stocks to Vectorvest and run it forward in time allowing Vectorvest to pick and choose from the set of potential candidates.

Of course it would be best if the whole 'worflow' could be performed within the same toolset. But as Ed says, Rome was not built in a day. Until then, a combination of tools seems a pragmatic compromise?

Rusty2

1st Feb '20

The problem with the Guru screens is you don’t know which shares are even included today, due to quarterly rebalancing those that qualify today or last month may not be included, some shares are in and out all the time. I think at least the screens should show the shares that are actually included. In my own screens it would also be useful to know when shares qualified.

George S

9th Feb '20

" In my own screens it would also be useful to know when shares qualified"

This is the single biggest problem in Stockopedia for me. A chart that has an arrow for 'qualified/triggered' would make it so much better.

I can do screen after screen but not knowing when a stock triggered or how it (or the rest, as a portfolio) did subsequently makes everything else meaningless.

12th Feb '20

Sorry Ed, that's not quite correct. You already have the ability to trace with your mouse on price chart of a company on its stock home page, the value of the StockRank. So the time machine exists. It should be easy to change that StockRank number to QualityRank, GrowthRank etc...or...perhaps even Screener trigger. Then I can run my own screen and know when a stock actually triggered in the past

Katandra

19th Jul '21

Yes, a gripe of Stockopedia for me is the lack of backtesting and creating portfolio screens like VectorVest does where you can backtest an idea or strategy. Other gripes are the lack of dates on many tables to ensure it is current, the Today discussions centre on UK and not your country and, Capitalisation is not in the relevant country currency. Even when given the chance to change to $, next time it is back to UK value instead.

Is Back-Testing possible and how about a 'Wayback Machine' ?

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Whatisgood

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