how do I correlate a single stock to anything?

[johnnyvento]

like an index, another stock, oil, etc. What I want is a statistic that is a percentage of the time the two move together, not a comparative strength index of above and below 1 which seems meaningless to me.

 

[Glenn]

like an index, another stock, oil, etc. What I want is a statistic that is a percentage of the time the two move together, not a comparative strength index of above and below 1 which seems meaningless to me.

Statistical correlation has a value between -1 (Negative and Opposite correlation) and +1 (Positive and Full correlation).

So if you are looking for two things that move together, look for Positive Correlation, the higher than 0 and the nearer to 1 the better. e.g. 0.8 is good correlation and essentially means that they move together 80% of the time.

Many charting packages can calculate the correlation between two symbols. It is done over a period of time which you specify.
A formula for calculating it is here half way down :-
Correlation

Glenn

 

[johnnyvento]

thanks Glenn. Can you name those charting packages? Also are you familiar with StockFetcher or any other scan writing site?

 

[Glenn]

Metastock, Tradestation are two packages that spring to mind. You could code it in Esignal.

Stockfetcher User Guide doesn't mention correlation. http://download.stockfetcher.com/download/sfuserguide2_0.pdf

What is a scan writing site ?
Are you looking for a scanner of the whole market ?
You could instead scan for some liquid stocks (say 20) and then check their correlation - all depends on what you are trying to do. Perhaps if you explained in more detail it would be easier to help you.
Glenn

 

[johnnyvento]

I just want to be able to correlate any stock with any other stock or any index as a percentage of time they move up together or down together on the same day (not even by the same amount) in a given period. The readout would be a simple percentage. Pretty simple really but I haven't figured out how to do it yet.

 

[Glenn]

.....I haven't figured out how to do it yet.

The formula shows you how to do the calculation yourself, and some packages will do it for you, so what exactly do you mean ?
Glenn

 

[johnnyvento]

I don't want to pay money just for this one analysis. Thanks for your help anyway.