yah, what throws me off is when you get a portfolio with active returns, and active risks…. i always just use the expected value of both and forget that i have to standardize the active risk part (even though it’s already given) in a portfolio context.
eg. if you are given active return and active risk for one portfolio, just divide one act ret / act risk to get information ratio…..
but if you are given a fund that invests in say 20% portfolio a, 30% portfolio b, 50% portfolio c, then you use the expected return for active return, but you have to square all the weights and multiply them by the squared active return, then square root the final number….. THEN divide act return by this number