In the context of minimax theory, we propose a new kind of risk,
normalized by a random variable, measurable with respect to the data. We
present a notion of optimality and a method to construct optimal procedures
accordingly. We apply this general setup to the problem of selecting
significant variables in Gaussian white noise. In particular, we show that our
method essentially improves the accuracy of estimation, in the sense of
giving explicit improved confidence sets in $L_2$-norm. Links to adaptive
estimation are discussed.