Chuckrox

I can understand implementation shortfall which is the differences of two abosolute returns.

I.S.(stock i) = (PNL(paper) - PNL(portfolio)) / (initial investment in paper trade)

The closer this number to zero, the better "trading".

M.A.I.S. (stock i)= I.S.(stock i) - Return(stock i)

This definition is not intuitive to me. How to interpret the number? The smaller the better or the larger the better? etc.

Thanks!