[R-SIG-Finance] Returns used to compute the alpha and the beta

[Benoit Schmid]

Good morning,

Brian G. Peterson wrote:
>  Return.excess may calculate what you are referring to as "alpha" if 
> by alpha you mean returns over a benchmark return, in which case you 
> would first run Return.excess using the benchmark return as the 
> parameter 'rf' and then cumulate your daily log returns to get a 
> cumulative return over some other periodicity (annual in your query).
First of all thanks for your answer.
There are several questions in my thread.

The first one is do you use net return or log return?

 From what I read, you always use log return.
Am I right?
If yes, why do you use log return instead of net returns?

Thanks in advance for your answer