No, in that case alpha would be the unexplained amount. If alpha is different from zero then the theory is inherently false and so the formula means nothing. Indeed, the formula has been shown to have a math mistake in it. See http://vimeo.com/87857357

Consider the following steps for calculating portfolio alpha:

You take a portfolio's returns, then do a regression against the market or benchmark return:

Portfolio return = alpha + (beta * benchmark return)

http://en.wikipedia.org/wiki/Beta_%28finance%29

Is that it? Where alpha is the amount of outperformance?