Beta Calculation


I will be taking up my first valuation project very soon and I am not sure about what time period I should use for calculating beta. I used a period of 1 year (daily values) for a particular company and the value I got was half of what was on the Reuters website. Can anyone tell me if there is any appropriate/ideal period?

Thank you

Daily data have far too much noise to be useful; weekly or monthly data have, in my experience, the highest signal-to-noise ratio.

A common data set for published values of beta is three years of monthly returns.

I wrote an article on beta that may be of some help here:

Thank you